diff --git a/Tests/test_bmp_reference.py b/Tests/test_bmp_reference.py
index 22ac9443e..0ad496135 100644
--- a/Tests/test_bmp_reference.py
+++ b/Tests/test_bmp_reference.py
@@ -10,7 +10,7 @@ from .helper import assert_image_similar
 base = os.path.join("Tests", "images", "bmp")
 
 
-def get_files(d, ext: str = ".bmp"):
+def get_files(d: str, ext: str = ".bmp") -> list[str]:
     return [
         os.path.join(base, d, f) for f in os.listdir(os.path.join(base, d)) if ext in f
     ]
@@ -29,7 +29,7 @@ def test_bad() -> None:
                 pass
 
 
-def test_questionable():
+def test_questionable() -> None:
     """These shouldn't crash/dos, but it's not well defined that these
     are in spec"""
     supported = [
@@ -80,7 +80,7 @@ def test_good() -> None:
         "rgb32bf.bmp": "rgb24.png",
     }
 
-    def get_compare(f):
+    def get_compare(f: str) -> str:
         name = os.path.split(f)[1]
         if name in file_map:
             return os.path.join(base, "html", file_map[name])
diff --git a/Tests/test_box_blur.py b/Tests/test_box_blur.py
index dfedb48d9..1f6ed6127 100644
--- a/Tests/test_box_blur.py
+++ b/Tests/test_box_blur.py
@@ -23,11 +23,11 @@ def test_imageops_box_blur() -> None:
     assert isinstance(i, Image.Image)
 
 
-def box_blur(image, radius: int = 1, n: int = 1):
+def box_blur(image: Image.Image, radius: float = 1, n: int = 1) -> Image.Image:
     return image._new(image.im.box_blur((radius, radius), n))
 
 
-def assert_image(im, data, delta: int = 0) -> None:
+def assert_image(im: Image.Image, data: list[list[int]], delta: int = 0) -> None:
     it = iter(im.getdata())
     for data_row in data:
         im_row = [next(it) for _ in range(im.size[0])]
@@ -37,7 +37,13 @@ def assert_image(im, data, delta: int = 0) -> None:
         next(it)
 
 
-def assert_blur(im, radius, data, passes: int = 1, delta: int = 0) -> None:
+def assert_blur(
+    im: Image.Image,
+    radius: float,
+    data: list[list[int]],
+    passes: int = 1,
+    delta: int = 0,
+) -> None:
     # check grayscale image
     assert_image(box_blur(im, radius, passes), data, delta)
     rgba = Image.merge("RGBA", (im, im, im, im))
diff --git a/Tests/test_file_apng.py b/Tests/test_file_apng.py
index f9edf6e98..395165b36 100644
--- a/Tests/test_file_apng.py
+++ b/Tests/test_file_apng.py
@@ -47,7 +47,7 @@ def test_apng_basic() -> None:
     "filename",
     ("Tests/images/apng/split_fdat.png", "Tests/images/apng/split_fdat_zero_chunk.png"),
 )
-def test_apng_fdat(filename) -> None:
+def test_apng_fdat(filename: str) -> None:
     with Image.open(filename) as im:
         im.seek(im.n_frames - 1)
         assert im.getpixel((0, 0)) == (0, 255, 0, 255)
@@ -338,7 +338,7 @@ def test_apng_syntax_errors() -> None:
         "sequence_fdat_fctl.png",
     ),
 )
-def test_apng_sequence_errors(test_file) -> None:
+def test_apng_sequence_errors(test_file: str) -> None:
     with pytest.raises(SyntaxError):
         with Image.open(f"Tests/images/apng/{test_file}") as im:
             im.seek(im.n_frames - 1)
@@ -681,7 +681,7 @@ def test_seek_after_close() -> None:
 @pytest.mark.parametrize("default_image", (True, False))
 @pytest.mark.parametrize("duplicate", (True, False))
 def test_different_modes_in_later_frames(
-    mode, default_image, duplicate, tmp_path: Path
+    mode: str, default_image: bool, duplicate: bool, tmp_path: Path
 ) -> None:
     test_file = str(tmp_path / "temp.png")
 
diff --git a/Tests/test_file_container.py b/Tests/test_file_container.py
index 4dba4be5d..813b444db 100644
--- a/Tests/test_file_container.py
+++ b/Tests/test_file_container.py
@@ -64,7 +64,7 @@ def test_seek_mode_2() -> None:
 
 
 @pytest.mark.parametrize("bytesmode", (True, False))
-def test_read_n0(bytesmode) -> None:
+def test_read_n0(bytesmode: bool) -> None:
     # Arrange
     with open(TEST_FILE, "rb" if bytesmode else "r") as fh:
         container = ContainerIO.ContainerIO(fh, 22, 100)
@@ -80,7 +80,7 @@ def test_read_n0(bytesmode) -> None:
 
 
 @pytest.mark.parametrize("bytesmode", (True, False))
-def test_read_n(bytesmode) -> None:
+def test_read_n(bytesmode: bool) -> None:
     # Arrange
     with open(TEST_FILE, "rb" if bytesmode else "r") as fh:
         container = ContainerIO.ContainerIO(fh, 22, 100)
@@ -96,7 +96,7 @@ def test_read_n(bytesmode) -> None:
 
 
 @pytest.mark.parametrize("bytesmode", (True, False))
-def test_read_eof(bytesmode) -> None:
+def test_read_eof(bytesmode: bool) -> None:
     # Arrange
     with open(TEST_FILE, "rb" if bytesmode else "r") as fh:
         container = ContainerIO.ContainerIO(fh, 22, 100)
@@ -112,7 +112,7 @@ def test_read_eof(bytesmode) -> None:
 
 
 @pytest.mark.parametrize("bytesmode", (True, False))
-def test_readline(bytesmode) -> None:
+def test_readline(bytesmode: bool) -> None:
     # Arrange
     with open(TEST_FILE, "rb" if bytesmode else "r") as fh:
         container = ContainerIO.ContainerIO(fh, 0, 120)
@@ -127,7 +127,7 @@ def test_readline(bytesmode) -> None:
 
 
 @pytest.mark.parametrize("bytesmode", (True, False))
-def test_readlines(bytesmode) -> None:
+def test_readlines(bytesmode: bool) -> None:
     # Arrange
     expected = [
         "This is line 1\n",
diff --git a/Tests/test_file_gif.py b/Tests/test_file_gif.py
index 3f550fd11..db9d3586c 100644
--- a/Tests/test_file_gif.py
+++ b/Tests/test_file_gif.py
@@ -3,6 +3,7 @@ from __future__ import annotations
 import warnings
 from io import BytesIO
 from pathlib import Path
+from typing import Generator
 
 import pytest
 
@@ -144,13 +145,13 @@ def test_strategy() -> None:
 
 
 def test_optimize() -> None:
-    def test_grayscale(optimize):
+    def test_grayscale(optimize: int) -> int:
         im = Image.new("L", (1, 1), 0)
         filename = BytesIO()
         im.save(filename, "GIF", optimize=optimize)
         return len(filename.getvalue())
 
-    def test_bilevel(optimize):
+    def test_bilevel(optimize: int) -> int:
         im = Image.new("1", (1, 1), 0)
         test_file = BytesIO()
         im.save(test_file, "GIF", optimize=optimize)
@@ -178,7 +179,9 @@ def test_optimize() -> None:
         (4, 513, 256),
     ),
 )
-def test_optimize_correctness(colors, size, expected_palette_length) -> None:
+def test_optimize_correctness(
+    colors: int, size: int, expected_palette_length: int
+) -> None:
     # 256 color Palette image, posterize to > 128 and < 128 levels.
     # Size bigger and smaller than 512x512.
     # Check the palette for number of colors allocated.
@@ -297,7 +300,7 @@ def test_roundtrip_save_all_1(tmp_path: Path) -> None:
         ("Tests/images/dispose_bgnd_rgba.gif", "RGBA"),
     ),
 )
-def test_loading_multiple_palettes(path, mode) -> None:
+def test_loading_multiple_palettes(path: str, mode: str) -> None:
     with Image.open(path) as im:
         assert im.mode == "P"
         first_frame_colors = im.palette.colors.keys()
@@ -347,9 +350,9 @@ def test_palette_handling(tmp_path: Path) -> None:
 def test_palette_434(tmp_path: Path) -> None:
     # see https://github.com/python-pillow/Pillow/issues/434
 
-    def roundtrip(im, *args, **kwargs):
+    def roundtrip(im: Image.Image, **kwargs: bool) -> Image.Image:
         out = str(tmp_path / "temp.gif")
-        im.copy().save(out, *args, **kwargs)
+        im.copy().save(out, **kwargs)
         reloaded = Image.open(out)
 
         return reloaded
@@ -429,7 +432,7 @@ def test_seek_rewind() -> None:
         ("Tests/images/iss634.gif", 42),
     ),
 )
-def test_n_frames(path, n_frames) -> None:
+def test_n_frames(path: str, n_frames: int) -> None:
     # Test is_animated before n_frames
     with Image.open(path) as im:
         assert im.is_animated == (n_frames != 1)
@@ -541,7 +544,10 @@ def test_dispose_background_transparency() -> None:
         ),
     ),
 )
-def test_transparent_dispose(loading_strategy, expected_colors) -> None:
+def test_transparent_dispose(
+    loading_strategy: GifImagePlugin.LoadingStrategy,
+    expected_colors: tuple[tuple[int | tuple[int, int, int, int], ...]],
+) -> None:
     GifImagePlugin.LOADING_STRATEGY = loading_strategy
     try:
         with Image.open("Tests/images/transparent_dispose.gif") as img:
@@ -889,7 +895,9 @@ def test_identical_frames(tmp_path: Path) -> None:
         1500,
     ),
 )
-def test_identical_frames_to_single_frame(duration, tmp_path: Path) -> None:
+def test_identical_frames_to_single_frame(
+    duration: int | list[int], tmp_path: Path
+) -> None:
     out = str(tmp_path / "temp.gif")
     im_list = [
         Image.new("L", (100, 100), "#000"),
@@ -1049,7 +1057,7 @@ def test_retain_comment_in_subsequent_frames(tmp_path: Path) -> None:
 def test_version(tmp_path: Path) -> None:
     out = str(tmp_path / "temp.gif")
 
-    def assert_version_after_save(im, version) -> None:
+    def assert_version_after_save(im: Image.Image, version: bytes) -> None:
         im.save(out)
         with Image.open(out) as reread:
             assert reread.info["version"] == version
@@ -1088,7 +1096,7 @@ def test_append_images(tmp_path: Path) -> None:
         assert reread.n_frames == 3
 
     # Tests appending using a generator
-    def im_generator(ims):
+    def im_generator(ims: list[Image.Image]) -> Generator[Image.Image, None, None]:
         yield from ims
 
     im.save(out, save_all=True, append_images=im_generator(ims))
diff --git a/Tests/test_file_mpo.py b/Tests/test_file_mpo.py
index 55b04a1e0..4fb00d699 100644
--- a/Tests/test_file_mpo.py
+++ b/Tests/test_file_mpo.py
@@ -2,6 +2,7 @@ from __future__ import annotations
 
 import warnings
 from io import BytesIO
+from typing import Any
 
 import pytest
 
@@ -19,7 +20,7 @@ test_files = ["Tests/images/sugarshack.mpo", "Tests/images/frozenpond.mpo"]
 pytestmark = skip_unless_feature("jpg")
 
 
-def roundtrip(im, **options):
+def roundtrip(im: Image.Image, **options: Any) -> Image.Image:
     out = BytesIO()
     im.save(out, "MPO", **options)
     test_bytes = out.tell()
@@ -30,7 +31,7 @@ def roundtrip(im, **options):
 
 
 @pytest.mark.parametrize("test_file", test_files)
-def test_sanity(test_file) -> None:
+def test_sanity(test_file: str) -> None:
     with Image.open(test_file) as im:
         im.load()
         assert im.mode == "RGB"
@@ -70,7 +71,7 @@ def test_context_manager() -> None:
 
 
 @pytest.mark.parametrize("test_file", test_files)
-def test_app(test_file) -> None:
+def test_app(test_file: str) -> None:
     # Test APP/COM reader (@PIL135)
     with Image.open(test_file) as im:
         assert im.applist[0][0] == "APP1"
@@ -82,7 +83,7 @@ def test_app(test_file) -> None:
 
 
 @pytest.mark.parametrize("test_file", test_files)
-def test_exif(test_file) -> None:
+def test_exif(test_file: str) -> None:
     with Image.open(test_file) as im_original:
         im_reloaded = roundtrip(im_original, save_all=True, exif=im_original.getexif())
 
@@ -143,7 +144,7 @@ def test_reload_exif_after_seek() -> None:
 
 
 @pytest.mark.parametrize("test_file", test_files)
-def test_mp(test_file) -> None:
+def test_mp(test_file: str) -> None:
     with Image.open(test_file) as im:
         mpinfo = im._getmp()
         assert mpinfo[45056] == b"0100"
@@ -168,7 +169,7 @@ def test_mp_no_data() -> None:
 
 
 @pytest.mark.parametrize("test_file", test_files)
-def test_mp_attribute(test_file) -> None:
+def test_mp_attribute(test_file: str) -> None:
     with Image.open(test_file) as im:
         mpinfo = im._getmp()
     for frame_number, mpentry in enumerate(mpinfo[0xB002]):
@@ -185,7 +186,7 @@ def test_mp_attribute(test_file) -> None:
 
 
 @pytest.mark.parametrize("test_file", test_files)
-def test_seek(test_file) -> None:
+def test_seek(test_file: str) -> None:
     with Image.open(test_file) as im:
         assert im.tell() == 0
         # prior to first image raises an error, both blatant and borderline
@@ -229,7 +230,7 @@ def test_eoferror() -> None:
 
 
 @pytest.mark.parametrize("test_file", test_files)
-def test_image_grab(test_file) -> None:
+def test_image_grab(test_file: str) -> None:
     with Image.open(test_file) as im:
         assert im.tell() == 0
         im0 = im.tobytes()
@@ -244,7 +245,7 @@ def test_image_grab(test_file) -> None:
 
 
 @pytest.mark.parametrize("test_file", test_files)
-def test_save(test_file) -> None:
+def test_save(test_file: str) -> None:
     with Image.open(test_file) as im:
         assert im.tell() == 0
         jpg0 = roundtrip(im)
diff --git a/Tests/test_file_ppm.py b/Tests/test_file_ppm.py
index 94f66ee7d..6e0fa32e4 100644
--- a/Tests/test_file_ppm.py
+++ b/Tests/test_file_ppm.py
@@ -70,7 +70,9 @@ def test_sanity() -> None:
         ),
     ),
 )
-def test_arbitrary_maxval(data, mode, pixels) -> None:
+def test_arbitrary_maxval(
+    data: bytes, mode: str, pixels: tuple[int | tuple[int, int, int], ...]
+) -> None:
     fp = BytesIO(data)
     with Image.open(fp) as im:
         assert im.size == (3, 1)
@@ -139,7 +141,7 @@ def test_pfm_big_endian(tmp_path: Path) -> None:
         b"Pf 1 1 -0.0 \0\0\0\0",
     ],
 )
-def test_pfm_invalid(data) -> None:
+def test_pfm_invalid(data: bytes) -> None:
     with pytest.raises(ValueError):
         with Image.open(BytesIO(data)):
             pass
@@ -162,7 +164,7 @@ def test_pfm_invalid(data) -> None:
         ),
     ),
 )
-def test_plain(plain_path, raw_path) -> None:
+def test_plain(plain_path: str, raw_path: str) -> None:
     with Image.open(plain_path) as im:
         assert_image_equal_tofile(im, raw_path)
 
@@ -186,7 +188,9 @@ def test_16bit_plain_pgm() -> None:
         (b"P3\n2 2\n255", b"0 0 0 001 1 1 2 2 2 255 255 255", 10**6),
     ),
 )
-def test_plain_data_with_comment(tmp_path: Path, header, data, comment_count) -> None:
+def test_plain_data_with_comment(
+    tmp_path: Path, header: bytes, data: bytes, comment_count: int
+) -> None:
     path1 = str(tmp_path / "temp1.ppm")
     path2 = str(tmp_path / "temp2.ppm")
     comment = b"# comment" * comment_count
@@ -199,7 +203,7 @@ def test_plain_data_with_comment(tmp_path: Path, header, data, comment_count) ->
 
 
 @pytest.mark.parametrize("data", (b"P1\n128 128\n", b"P3\n128 128\n255\n"))
-def test_plain_truncated_data(tmp_path: Path, data) -> None:
+def test_plain_truncated_data(tmp_path: Path, data: bytes) -> None:
     path = str(tmp_path / "temp.ppm")
     with open(path, "wb") as f:
         f.write(data)
@@ -210,7 +214,7 @@ def test_plain_truncated_data(tmp_path: Path, data) -> None:
 
 
 @pytest.mark.parametrize("data", (b"P1\n128 128\n1009", b"P3\n128 128\n255\n100A"))
-def test_plain_invalid_data(tmp_path: Path, data) -> None:
+def test_plain_invalid_data(tmp_path: Path, data: bytes) -> None:
     path = str(tmp_path / "temp.ppm")
     with open(path, "wb") as f:
         f.write(data)
@@ -227,7 +231,7 @@ def test_plain_invalid_data(tmp_path: Path, data) -> None:
         b"P3\n128 128\n255\n012345678910 0",  # token too long
     ),
 )
-def test_plain_ppm_token_too_long(tmp_path: Path, data) -> None:
+def test_plain_ppm_token_too_long(tmp_path: Path, data: bytes) -> None:
     path = str(tmp_path / "temp.ppm")
     with open(path, "wb") as f:
         f.write(data)
@@ -313,7 +317,7 @@ def test_not_enough_image_data(tmp_path: Path) -> None:
 
 
 @pytest.mark.parametrize("maxval", (b"0", b"65536"))
-def test_invalid_maxval(maxval, tmp_path: Path) -> None:
+def test_invalid_maxval(maxval: bytes, tmp_path: Path) -> None:
     path = str(tmp_path / "temp.ppm")
     with open(path, "wb") as f:
         f.write(b"P6\n3 1 " + maxval)
@@ -351,7 +355,7 @@ def test_mimetypes(tmp_path: Path) -> None:
 
 
 @pytest.mark.parametrize("buffer", (True, False))
-def test_save_stdout(buffer) -> None:
+def test_save_stdout(buffer: bool) -> None:
     old_stdout = sys.stdout
 
     if buffer:
diff --git a/Tests/test_file_sgi.py b/Tests/test_file_sgi.py
index 92aea0735..e13a8019e 100644
--- a/Tests/test_file_sgi.py
+++ b/Tests/test_file_sgi.py
@@ -72,7 +72,7 @@ def test_invalid_file() -> None:
 
 
 def test_write(tmp_path: Path) -> None:
-    def roundtrip(img) -> None:
+    def roundtrip(img: Image.Image) -> None:
         out = str(tmp_path / "temp.sgi")
         img.save(out, format="sgi")
         assert_image_equal_tofile(img, out)
diff --git a/Tests/test_image_frombytes.py b/Tests/test_image_frombytes.py
index 6474daba1..98c0ea0b4 100644
--- a/Tests/test_image_frombytes.py
+++ b/Tests/test_image_frombytes.py
@@ -8,7 +8,7 @@ from .helper import assert_image_equal, hopper
 
 
 @pytest.mark.parametrize("data_type", ("bytes", "memoryview"))
-def test_sanity(data_type) -> None:
+def test_sanity(data_type: str) -> None:
     im1 = hopper()
 
     data = im1.tobytes()
diff --git a/Tests/test_image_load.py b/Tests/test_image_load.py
index 5b1a9ee2d..0605821e0 100644
--- a/Tests/test_image_load.py
+++ b/Tests/test_image_load.py
@@ -26,7 +26,7 @@ def test_close() -> None:
         im.getpixel((0, 0))
 
 
-def test_close_after_load(caplog) -> None:
+def test_close_after_load(caplog: pytest.LogCaptureFixture) -> None:
     im = Image.open("Tests/images/hopper.gif")
     im.load()
     with caplog.at_level(logging.DEBUG):
diff --git a/Tests/test_imagedraw.py b/Tests/test_imagedraw.py
index 86d25b1eb..c02ac49dd 100644
--- a/Tests/test_imagedraw.py
+++ b/Tests/test_imagedraw.py
@@ -74,7 +74,14 @@ def test_mode_mismatch() -> None:
 
 @pytest.mark.parametrize("bbox", BBOX)
 @pytest.mark.parametrize("start, end", ((0, 180), (0.5, 180.4)))
-def test_arc(bbox, start, end) -> None:
+def test_arc(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int],
+    start: float,
+    end: float,
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -87,7 +94,12 @@ def test_arc(bbox, start, end) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_arc_end_le_start(bbox) -> None:
+def test_arc_end_le_start(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -102,7 +114,12 @@ def test_arc_end_le_start(bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_arc_no_loops(bbox) -> None:
+def test_arc_no_loops(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # No need to go in loops
     # Arrange
     im = Image.new("RGB", (W, H))
@@ -118,7 +135,12 @@ def test_arc_no_loops(bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_arc_width(bbox) -> None:
+def test_arc_width(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -131,7 +153,12 @@ def test_arc_width(bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_arc_width_pieslice_large(bbox) -> None:
+def test_arc_width_pieslice_large(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Tests an arc with a large enough width that it is a pieslice
     # Arrange
     im = Image.new("RGB", (W, H))
@@ -145,7 +172,12 @@ def test_arc_width_pieslice_large(bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_arc_width_fill(bbox) -> None:
+def test_arc_width_fill(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -158,7 +190,12 @@ def test_arc_width_fill(bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_arc_width_non_whole_angle(bbox) -> None:
+def test_arc_width_non_whole_angle(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -200,7 +237,13 @@ def test_bitmap() -> None:
 
 @pytest.mark.parametrize("mode", ("RGB", "L"))
 @pytest.mark.parametrize("bbox", BBOX)
-def test_chord(mode, bbox) -> None:
+def test_chord(
+    mode: str,
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int],
+) -> None:
     # Arrange
     im = Image.new(mode, (W, H))
     draw = ImageDraw.Draw(im)
@@ -214,7 +257,12 @@ def test_chord(mode, bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_chord_width(bbox) -> None:
+def test_chord_width(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -227,7 +275,12 @@ def test_chord_width(bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_chord_width_fill(bbox) -> None:
+def test_chord_width_fill(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -240,7 +293,12 @@ def test_chord_width_fill(bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_chord_zero_width(bbox) -> None:
+def test_chord_zero_width(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -266,7 +324,13 @@ def test_chord_too_fat() -> None:
 
 @pytest.mark.parametrize("mode", ("RGB", "L"))
 @pytest.mark.parametrize("bbox", BBOX)
-def test_ellipse(mode, bbox) -> None:
+def test_ellipse(
+    mode: str,
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int],
+) -> None:
     # Arrange
     im = Image.new(mode, (W, H))
     draw = ImageDraw.Draw(im)
@@ -280,7 +344,12 @@ def test_ellipse(mode, bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_ellipse_translucent(bbox) -> None:
+def test_ellipse_translucent(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im, "RGBA")
@@ -317,7 +386,12 @@ def test_ellipse_symmetric() -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_ellipse_width(bbox) -> None:
+def test_ellipse_width(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -342,7 +416,12 @@ def test_ellipse_width_large() -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_ellipse_width_fill(bbox) -> None:
+def test_ellipse_width_fill(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -355,7 +434,12 @@ def test_ellipse_width_fill(bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_ellipse_zero_width(bbox) -> None:
+def test_ellipse_zero_width(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -367,7 +451,7 @@ def test_ellipse_zero_width(bbox) -> None:
     assert_image_equal_tofile(im, "Tests/images/imagedraw_ellipse_zero_width.png")
 
 
-def ellipse_various_sizes_helper(filled):
+def ellipse_various_sizes_helper(filled: bool) -> Image.Image:
     ellipse_sizes = range(32)
     image_size = sum(ellipse_sizes) + len(ellipse_sizes) + 1
     im = Image.new("RGB", (image_size, image_size))
@@ -409,7 +493,12 @@ def test_ellipse_various_sizes_filled() -> None:
 
 
 @pytest.mark.parametrize("points", POINTS)
-def test_line(points) -> None:
+def test_line(
+    points: tuple[tuple[int, int], ...]
+    | list[tuple[int, int]]
+    | tuple[int, ...]
+    | list[int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -482,7 +571,14 @@ def test_transform() -> None:
 
 @pytest.mark.parametrize("bbox", BBOX)
 @pytest.mark.parametrize("start, end", ((-92, 46), (-92.2, 46.2)))
-def test_pieslice(bbox, start, end) -> None:
+def test_pieslice(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int],
+    start: float,
+    end: float,
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -495,7 +591,12 @@ def test_pieslice(bbox, start, end) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_pieslice_width(bbox) -> None:
+def test_pieslice_width(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -508,7 +609,12 @@ def test_pieslice_width(bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_pieslice_width_fill(bbox) -> None:
+def test_pieslice_width_fill(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -522,7 +628,12 @@ def test_pieslice_width_fill(bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_pieslice_zero_width(bbox) -> None:
+def test_pieslice_zero_width(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -577,7 +688,12 @@ def test_pieslice_no_spikes() -> None:
 
 
 @pytest.mark.parametrize("points", POINTS)
-def test_point(points) -> None:
+def test_point(
+    points: tuple[tuple[int, int], ...]
+    | list[tuple[int, int]]
+    | tuple[int, ...]
+    | list[int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -602,7 +718,12 @@ def test_point_I16() -> None:
 
 
 @pytest.mark.parametrize("points", POINTS)
-def test_polygon(points) -> None:
+def test_polygon(
+    points: tuple[tuple[int, int], ...]
+    | list[tuple[int, int]]
+    | tuple[int, ...]
+    | list[int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -616,7 +737,9 @@ def test_polygon(points) -> None:
 
 @pytest.mark.parametrize("mode", ("RGB", "L"))
 @pytest.mark.parametrize("kite_points", KITE_POINTS)
-def test_polygon_kite(mode, kite_points) -> None:
+def test_polygon_kite(
+    mode: str, kite_points: tuple[tuple[int, int], ...] | list[tuple[int, int]]
+) -> None:
     # Test drawing lines of different gradients (dx>dy, dy>dx) and
     # vertical (dx==0) and horizontal (dy==0) lines
     # Arrange
@@ -673,7 +796,12 @@ def test_polygon_translucent() -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_rectangle(bbox) -> None:
+def test_rectangle(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -700,7 +828,12 @@ def test_big_rectangle() -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_rectangle_width(bbox) -> None:
+def test_rectangle_width(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -714,7 +847,12 @@ def test_rectangle_width(bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_rectangle_width_fill(bbox) -> None:
+def test_rectangle_width_fill(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -728,7 +866,12 @@ def test_rectangle_width_fill(bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_rectangle_zero_width(bbox) -> None:
+def test_rectangle_zero_width(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -741,7 +884,12 @@ def test_rectangle_zero_width(bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_rectangle_I16(bbox) -> None:
+def test_rectangle_I16(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("I;16", (W, H))
     draw = ImageDraw.Draw(im)
@@ -754,7 +902,12 @@ def test_rectangle_I16(bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_rectangle_translucent_outline(bbox) -> None:
+def test_rectangle_translucent_outline(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im, "RGBA")
@@ -772,7 +925,11 @@ def test_rectangle_translucent_outline(bbox) -> None:
     "xy",
     [(10, 20, 190, 180), ([10, 20], [190, 180]), ((10, 20), (190, 180))],
 )
-def test_rounded_rectangle(xy) -> None:
+def test_rounded_rectangle(
+    xy: tuple[int, int, int, int]
+    | tuple[list[int]]
+    | tuple[tuple[int, int], tuple[int, int]]
+) -> None:
     # Arrange
     im = Image.new("RGB", (200, 200))
     draw = ImageDraw.Draw(im)
@@ -789,7 +946,7 @@ def test_rounded_rectangle(xy) -> None:
 @pytest.mark.parametrize("bottom_right", (True, False))
 @pytest.mark.parametrize("bottom_left", (True, False))
 def test_rounded_rectangle_corners(
-    top_left, top_right, bottom_right, bottom_left
+    top_left: bool, top_right: bool, bottom_right: bool, bottom_left: bool
 ) -> None:
     corners = (top_left, top_right, bottom_right, bottom_left)
 
@@ -824,7 +981,9 @@ def test_rounded_rectangle_corners(
         ((10, 20, 190, 181), 85, "height"),
     ],
 )
-def test_rounded_rectangle_non_integer_radius(xy, radius, type) -> None:
+def test_rounded_rectangle_non_integer_radius(
+    xy: tuple[int, int, int, int], radius: float, type: str
+) -> None:
     # Arrange
     im = Image.new("RGB", (200, 200))
     draw = ImageDraw.Draw(im)
@@ -840,7 +999,12 @@ def test_rounded_rectangle_non_integer_radius(xy, radius, type) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_rounded_rectangle_zero_radius(bbox) -> None:
+def test_rounded_rectangle_zero_radius(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
@@ -862,7 +1026,9 @@ def test_rounded_rectangle_zero_radius(bbox) -> None:
         ((20, 20, 80, 80), "both"),
     ],
 )
-def test_rounded_rectangle_translucent(xy, suffix) -> None:
+def test_rounded_rectangle_translucent(
+    xy: tuple[int, int, int, int], suffix: str
+) -> None:
     # Arrange
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im, "RGBA")
@@ -879,7 +1045,12 @@ def test_rounded_rectangle_translucent(xy, suffix) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_floodfill(bbox) -> None:
+def test_floodfill(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     red = ImageColor.getrgb("red")
 
     for mode, value in [("L", 1), ("RGBA", (255, 0, 0, 0)), ("RGB", red)]:
@@ -912,7 +1083,12 @@ def test_floodfill(bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_floodfill_border(bbox) -> None:
+def test_floodfill_border(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # floodfill() is experimental
 
     # Arrange
@@ -934,7 +1110,12 @@ def test_floodfill_border(bbox) -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_floodfill_thresh(bbox) -> None:
+def test_floodfill_thresh(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # floodfill() is experimental
 
     # Arrange
@@ -968,8 +1149,11 @@ def test_floodfill_not_negative() -> None:
 
 
 def create_base_image_draw(
-    size, mode=DEFAULT_MODE, background1=WHITE, background2=GRAY
-):
+    size: tuple[int, int],
+    mode: str = DEFAULT_MODE,
+    background1: tuple[int, int, int] = WHITE,
+    background2: tuple[int, int, int] = GRAY,
+) -> tuple[Image.Image, ImageDraw.ImageDraw]:
     img = Image.new(mode, size, background1)
     for x in range(0, size[0]):
         for y in range(0, size[1]):
@@ -1003,7 +1187,7 @@ def test_triangle_right() -> None:
     "fill, suffix",
     ((BLACK, "width"), (None, "width_no_fill")),
 )
-def test_triangle_right_width(fill, suffix) -> None:
+def test_triangle_right_width(fill: tuple[int, int, int] | None, suffix: str) -> None:
     img, draw = create_base_image_draw((100, 100))
     draw.polygon([(15, 25), (85, 25), (50, 60)], fill, WHITE, width=5)
     assert_image_equal_tofile(
@@ -1235,7 +1419,7 @@ def test_wide_line_larger_than_int() -> None:
         ],
     ],
 )
-def test_line_joint(xy) -> None:
+def test_line_joint(xy: list[tuple[int, int]] | tuple[int, ...] | list[int]) -> None:
     im = Image.new("RGB", (500, 325))
     draw = ImageDraw.Draw(im)
 
@@ -1388,7 +1572,12 @@ def test_default_font_size() -> None:
 
 
 @pytest.mark.parametrize("bbox", BBOX)
-def test_same_color_outline(bbox) -> None:
+def test_same_color_outline(
+    bbox: tuple[tuple[int, int], tuple[int, int]]
+    | list[tuple[int, int]]
+    | list[int]
+    | tuple[int, int, int, int]
+) -> None:
     # Prepare shape
     x0, y0 = 5, 5
     x1, y1 = 5, 50
@@ -1402,7 +1591,8 @@ def test_same_color_outline(bbox) -> None:
 
     # Begin
     for mode in ["RGB", "L"]:
-        for fill, outline in [["red", None], ["red", "red"], ["red", "#f00"]]:
+        fill = "red"
+        for outline in [None, "red", "#f00"]:
             for operation, args in {
                 "chord": [bbox, 0, 180],
                 "ellipse": [bbox],
@@ -1417,6 +1607,7 @@ def test_same_color_outline(bbox) -> None:
 
                 # Act
                 draw_method = getattr(draw, operation)
+                assert isinstance(args, list)
                 args += [fill, outline]
                 draw_method(*args)
 
@@ -1434,7 +1625,9 @@ def test_same_color_outline(bbox) -> None:
         (3, "triangle_width", {"width": 5, "outline": "yellow"}),
     ],
 )
-def test_draw_regular_polygon(n_sides, polygon_name, args) -> None:
+def test_draw_regular_polygon(
+    n_sides: int, polygon_name: str, args: dict[str, int | str]
+) -> None:
     im = Image.new("RGBA", size=(W, H), color=(255, 0, 0, 0))
     filename = f"Tests/images/imagedraw_{polygon_name}.png"
     draw = ImageDraw.Draw(im)
@@ -1471,7 +1664,9 @@ def test_draw_regular_polygon(n_sides, polygon_name, args) -> None:
         ),
     ],
 )
-def test_compute_regular_polygon_vertices(n_sides, expected_vertices) -> None:
+def test_compute_regular_polygon_vertices(
+    n_sides: int, expected_vertices: list[tuple[float, float]]
+) -> None:
     bounding_circle = (W // 2, H // 2, 25)
     vertices = ImageDraw._compute_regular_polygon_vertices(bounding_circle, n_sides, 0)
     assert vertices == expected_vertices
@@ -1569,7 +1764,7 @@ def test_polygon2() -> None:
 
 
 @pytest.mark.parametrize("xy", ((1, 1, 0, 1), (1, 1, 1, 0)))
-def test_incorrectly_ordered_coordinates(xy) -> None:
+def test_incorrectly_ordered_coordinates(xy: tuple[int, int, int, int]) -> None:
     im = Image.new("RGB", (W, H))
     draw = ImageDraw.Draw(im)
     with pytest.raises(ValueError):
diff --git a/Tests/test_imagetk.py b/Tests/test_imagetk.py
index a216bd21d..b607b8c43 100644
--- a/Tests/test_imagetk.py
+++ b/Tests/test_imagetk.py
@@ -57,7 +57,7 @@ def test_kw() -> None:
 
 
 @pytest.mark.parametrize("mode", TK_MODES)
-def test_photoimage(mode) -> None:
+def test_photoimage(mode: str) -> None:
     # test as image:
     im = hopper(mode)
 
@@ -79,7 +79,7 @@ def test_photoimage_apply_transparency() -> None:
 
 
 @pytest.mark.parametrize("mode", TK_MODES)
-def test_photoimage_blank(mode) -> None:
+def test_photoimage_blank(mode: str) -> None:
     # test a image using mode/size:
     im_tk = ImageTk.PhotoImage(mode, (100, 100))
 
diff --git a/Tests/test_lib_pack.py b/Tests/test_lib_pack.py
index c8d6d33d2..629a6dc7a 100644
--- a/Tests/test_lib_pack.py
+++ b/Tests/test_lib_pack.py
@@ -10,7 +10,13 @@ X = 255
 
 
 class TestLibPack:
-    def assert_pack(self, mode, rawmode, data, *pixels) -> None:
+    def assert_pack(
+        self,
+        mode: str,
+        rawmode: str,
+        data: int | bytes,
+        *pixels: int | float | tuple[int, ...],
+    ) -> None:
         """
         data - either raw bytes with data or just number of bytes in rawmode.
         """
@@ -228,7 +234,13 @@ class TestLibPack:
 
 
 class TestLibUnpack:
-    def assert_unpack(self, mode, rawmode, data, *pixels) -> None:
+    def assert_unpack(
+        self,
+        mode: str,
+        rawmode: str,
+        data: int | bytes,
+        *pixels: int | float | tuple[int, ...],
+    ) -> None:
         """
         data - either raw bytes with data or just number of bytes in rawmode.
         """
diff --git a/Tests/test_mode_i16.py b/Tests/test_mode_i16.py
index f2540bb46..903f7e0c6 100644
--- a/Tests/test_mode_i16.py
+++ b/Tests/test_mode_i16.py
@@ -11,7 +11,7 @@ from .helper import hopper
 original = hopper().resize((32, 32)).convert("I")
 
 
-def verify(im1) -> None:
+def verify(im1: Image.Image) -> None:
     im2 = original.copy()
     assert im1.size == im2.size
     pix1 = im1.load()
@@ -27,7 +27,7 @@ def verify(im1) -> None:
 
 
 @pytest.mark.parametrize("mode", ("L", "I;16", "I;16B", "I;16L", "I"))
-def test_basic(tmp_path: Path, mode) -> None:
+def test_basic(tmp_path: Path, mode: str) -> None:
     # PIL 1.1 has limited support for 16-bit image data.  Check that
     # create/copy/transform and save works as expected.
 
@@ -78,7 +78,7 @@ def test_basic(tmp_path: Path, mode) -> None:
 
 
 def test_tobytes() -> None:
-    def tobytes(mode):
+    def tobytes(mode: str) -> Image.Image:
         return Image.new(mode, (1, 1), 1).tobytes()
 
     order = 1 if Image._ENDIAN == "<" else -1