diff --git a/benchmarks/benchmarks/_utils.py b/benchmarks/benchmarks/_utils.py
index 810ace74fd..93bb4623f9 100644
--- a/benchmarks/benchmarks/_utils.py
+++ b/benchmarks/benchmarks/_utils.py
@@ -14,7 +14,8 @@
 import scanpy as sc
 
 if TYPE_CHECKING:
-    from collections.abc import Callable, Sequence, Set
+    from collections.abc import Callable, Sequence
+    from collections.abc import Set as AbstractSet
     from typing import Literal, Protocol, TypeVar
 
     from anndata import AnnData
@@ -22,7 +23,7 @@
     C = TypeVar("C", bound=Callable)
 
     class ParamSkipper(Protocol):
-        def __call__(self, **skipped: Set) -> Callable[[C], C]: ...
+        def __call__(self, **skipped: AbstractSet) -> Callable[[C], C]: ...
 
     Dataset = Literal["pbmc68k_reduced", "pbmc3k", "bmmc", "lung93k"]
     KeyX = Literal[None, "off-axis"]
@@ -195,7 +196,7 @@ def param_skipper(
     b 5
     """
 
-    def skip(**skipped: Set) -> Callable[[C], C]:
+    def skip(**skipped: AbstractSet) -> Callable[[C], C]:
         skipped_combs = [
             tuple(record.values())
             for record in (
diff --git a/pyproject.toml b/pyproject.toml
index dda000d790..e983d04a97 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -232,6 +232,7 @@ select = [
     "TID251",  # Banned imports
     "ICN",     # Follow import conventions
     "PTH",     # Pathlib instead of os.path
+    "PYI",     # Typing
     "PLR0917", # Ban APIs with too many positional parameters
     "FBT",     # No positional boolean parameters
     "PT",      # Pytest style
@@ -246,6 +247,8 @@ ignore = [
     "E262",
     # allow I, O, l as variable names -> I is the identity matrix, i, j, k, l is reasonable indexing notation
     "E741",
+    # `Literal["..."] | str` is useful for autocompletion
+    "PYI051",
 ]
 [tool.ruff.lint.per-file-ignores]
 # Do not assign a lambda expression, use a def
diff --git a/src/scanpy/_settings.py b/src/scanpy/_settings.py
index fa44fc8492..54b51b6420 100644
--- a/src/scanpy/_settings.py
+++ b/src/scanpy/_settings.py
@@ -19,7 +19,7 @@
 
     # Collected from the print_* functions in matplotlib.backends
     _Format = (
-        Literal["png", "jpg", "tif", "tiff"]
+        Literal["png", "jpg", "tif", "tiff"]  # noqa: PYI030
         | Literal["pdf", "ps", "eps", "svg", "svgz", "pgf"]
         | Literal["raw", "rgba"]
     )
@@ -340,7 +340,7 @@ def max_memory(self) -> int | float:
         return self._max_memory
 
     @max_memory.setter
-    def max_memory(self, max_memory: int | float):
+    def max_memory(self, max_memory: float):
         _type_check(max_memory, "max_memory", (int, float))
         self._max_memory = max_memory
 
diff --git a/src/scanpy/_utils/__init__.py b/src/scanpy/_utils/__init__.py
index 8e886d1ff1..066e23f667 100644
--- a/src/scanpy/_utils/__init__.py
+++ b/src/scanpy/_utils/__init__.py
@@ -12,14 +12,21 @@
 import re
 import sys
 import warnings
-from collections import namedtuple
 from contextlib import contextmanager, suppress
 from enum import Enum
 from functools import partial, reduce, singledispatch, wraps
 from operator import mul, or_, truediv
 from textwrap import dedent
 from types import MethodType, ModuleType, UnionType
-from typing import TYPE_CHECKING, Literal, Union, get_args, get_origin, overload
+from typing import (
+    TYPE_CHECKING,
+    Literal,
+    NamedTuple,
+    Union,
+    get_args,
+    get_origin,
+    overload,
+)
 from weakref import WeakSet
 
 import h5py
@@ -297,6 +304,11 @@ def get_igraph_from_adjacency(adjacency, directed=None):
 # --------------------------------------------------------------------------------
 
 
+class AssoResult(NamedTuple):
+    asso_names: list[str]
+    asso_matrix: NDArray[np.floating]
+
+
 def compute_association_matrix_of_groups(
     adata: AnnData,
     prediction: str,
@@ -305,7 +317,7 @@ def compute_association_matrix_of_groups(
     normalization: Literal["prediction", "reference"] = "prediction",
     threshold: float = 0.01,
     max_n_names: int | None = 2,
-):
+) -> AssoResult:
     """Compute overlaps between groups.
 
     See ``identify_groups`` for identifying the groups.
@@ -347,8 +359,8 @@ def compute_association_matrix_of_groups(
                 f"Ignoring category {cat!r} "
                 "as it’s in `settings.categories_to_ignore`."
             )
-    asso_names = []
-    asso_matrix = []
+    asso_names: list[str] = []
+    asso_matrix: list[list[float]] = []
     for ipred_group, pred_group in enumerate(adata.obs[prediction].cat.categories):
         if "?" in pred_group:
             pred_group = str(ipred_group)
@@ -381,13 +393,12 @@ def compute_association_matrix_of_groups(
             if asso_matrix[-1][i] > threshold
         ]
         asso_names += ["\n".join(name_list_pred[:max_n_names])]
-    Result = namedtuple(
-        "compute_association_matrix_of_groups", ["asso_names", "asso_matrix"]
-    )
-    return Result(asso_names=asso_names, asso_matrix=np.array(asso_matrix))
+    return AssoResult(asso_names=asso_names, asso_matrix=np.array(asso_matrix))
 
 
-def get_associated_colors_of_groups(reference_colors, asso_matrix):
+def get_associated_colors_of_groups(
+    reference_colors: Mapping[int, str], asso_matrix: NDArray[np.floating]
+) -> list[dict[str, float]]:
     return [
         {
             reference_colors[i_ref]: asso_matrix[i_pred, i_ref]
diff --git a/src/scanpy/cli.py b/src/scanpy/cli.py
index 04b75c8b74..c934292dba 100644
--- a/src/scanpy/cli.py
+++ b/src/scanpy/cli.py
@@ -11,7 +11,7 @@
 from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
-    from collections.abc import Generator, Mapping, Sequence
+    from collections.abc import Iterator, Mapping, Sequence
     from subprocess import CompletedProcess
     from typing import Any
 
@@ -64,7 +64,7 @@ def __delitem__(self, k: str) -> None:
 
     # These methods retrieve the command list or help with doing it
 
-    def __iter__(self) -> Generator[str, None, None]:
+    def __iter__(self) -> Iterator[str]:
         yield from self.parser_map
         yield from self.commands
 
diff --git a/src/scanpy/get/_aggregated.py b/src/scanpy/get/_aggregated.py
index 2d2739491e..13ca54b5c4 100644
--- a/src/scanpy/get/_aggregated.py
+++ b/src/scanpy/get/_aggregated.py
@@ -160,7 +160,7 @@ def median(self) -> Array:
         return np.array(medians)
 
 
-def _power(X: Array, power: float | int) -> Array:
+def _power(X: Array, power: float) -> Array:
     """\
     Generate elementwise power of a matrix.
 
diff --git a/src/scanpy/plotting/_anndata.py b/src/scanpy/plotting/_anndata.py
index 0ae810b2c7..a93d55699b 100755
--- a/src/scanpy/plotting/_anndata.py
+++ b/src/scanpy/plotting/_anndata.py
@@ -104,7 +104,7 @@ def scatter(
     components: str | Collection[str] | None = None,
     projection: Literal["2d", "3d"] = "2d",
     legend_loc: _LegendLoc | None = "right margin",
-    legend_fontsize: int | float | _FontSize | None = None,
+    legend_fontsize: float | _FontSize | None = None,
     legend_fontweight: int | _FontWeight | None = None,
     legend_fontoutline: float | None = None,
     color_map: str | Colormap | None = None,
@@ -112,7 +112,7 @@ def scatter(
     frameon: bool | None = None,
     right_margin: float | None = None,
     left_margin: float | None = None,
-    size: int | float | None = None,
+    size: float | None = None,
     marker: str | Sequence[str] = ".",
     title: str | Collection[str] | None = None,
     show: bool | None = None,
@@ -232,7 +232,7 @@ def _scatter_obs(
     components: str | Collection[str] | None = None,
     projection: Literal["2d", "3d"] = "2d",
     legend_loc: _LegendLoc | None = "right margin",
-    legend_fontsize: int | float | _FontSize | None = None,
+    legend_fontsize: float | _FontSize | None = None,
     legend_fontweight: int | _FontWeight | None = None,
     legend_fontoutline: float | None = None,
     color_map: str | Colormap | None = None,
@@ -240,7 +240,7 @@ def _scatter_obs(
     frameon: bool | None = None,
     right_margin: float | None = None,
     left_margin: float | None = None,
-    size: int | float | None = None,
+    size: float | None = None,
     marker: str | Sequence[str] = ".",
     title: str | Collection[str] | None = None,
     show: bool | None = None,
diff --git a/src/scanpy/plotting/_stacked_violin.py b/src/scanpy/plotting/_stacked_violin.py
index 691dd863d0..e47680facc 100644
--- a/src/scanpy/plotting/_stacked_violin.py
+++ b/src/scanpy/plotting/_stacked_violin.py
@@ -273,7 +273,7 @@ def style(
         cmap: Colormap | str | None | Empty = _empty,
         stripplot: bool | Empty = _empty,
         jitter: float | bool | Empty = _empty,
-        jitter_size: int | float | Empty = _empty,
+        jitter_size: float | Empty = _empty,
         linewidth: float | None | Empty = _empty,
         row_palette: str | None | Empty = _empty,
         density_norm: DensityNorm | Empty = _empty,
@@ -470,8 +470,8 @@ def _make_rows_of_violinplots(
         _matrix,
         colormap_array,
         _color_df,
-        x_spacer_size: float | int,
-        y_spacer_size: float | int,
+        x_spacer_size: float,
+        y_spacer_size: float,
         x_axis_order,
     ):
         import seaborn as sns  # Slow import, only import if called
@@ -699,7 +699,7 @@ def stacked_violin(
     cmap: Colormap | str | None = StackedViolin.DEFAULT_COLORMAP,
     stripplot: bool = StackedViolin.DEFAULT_STRIPPLOT,
     jitter: float | bool = StackedViolin.DEFAULT_JITTER,
-    size: int | float = StackedViolin.DEFAULT_JITTER_SIZE,
+    size: float = StackedViolin.DEFAULT_JITTER_SIZE,
     row_palette: str | None = StackedViolin.DEFAULT_ROW_PALETTE,
     density_norm: DensityNorm | Empty = _empty,
     yticklabels: bool = StackedViolin.DEFAULT_PLOT_YTICKLABELS,
diff --git a/src/scanpy/plotting/_tools/__init__.py b/src/scanpy/plotting/_tools/__init__.py
index 837d3791e8..a421f6b94a 100644
--- a/src/scanpy/plotting/_tools/__init__.py
+++ b/src/scanpy/plotting/_tools/__init__.py
@@ -1209,7 +1209,7 @@ def rank_genes_groups_violin(
     split: bool = True,
     density_norm: DensityNorm = "width",
     strip: bool = True,
-    jitter: int | float | bool = True,
+    jitter: float | bool = True,
     size: int = 1,
     ax: Axes | None = None,
     show: bool | None = None,
@@ -1428,7 +1428,7 @@ def embedding_density(
     *,
     key: str | None = None,
     groupby: str | None = None,
-    group: str | Sequence[str] | None | None = "all",
+    group: str | Sequence[str] | None = "all",
     color_map: Colormap | str = "YlOrRd",
     bg_dotsize: int | None = 80,
     fg_dotsize: int | None = 180,
diff --git a/src/scanpy/plotting/_tools/paga.py b/src/scanpy/plotting/_tools/paga.py
index 29408735b6..7e62d46eac 100644
--- a/src/scanpy/plotting/_tools/paga.py
+++ b/src/scanpy/plotting/_tools/paga.py
@@ -73,7 +73,7 @@ def paga_compare(
     components=None,
     projection: Literal["2d", "3d"] = "2d",
     legend_loc: _LegendLoc | None = "on data",
-    legend_fontsize: int | float | _FontSize | None = None,
+    legend_fontsize: float | _FontSize | None = None,
     legend_fontweight: int | _FontWeight = "bold",
     legend_fontoutline=None,
     color_map=None,
@@ -1053,7 +1053,7 @@ def paga_path(
     show_node_names: bool = True,
     show_yticks: bool = True,
     show_colorbar: bool = True,
-    legend_fontsize: int | float | _FontSize | None = None,
+    legend_fontsize: float | _FontSize | None = None,
     legend_fontweight: int | _FontWeight | None = None,
     normalize_to_zero_one: bool = False,
     as_heatmap: bool = True,
diff --git a/src/scanpy/plotting/_tools/scatterplots.py b/src/scanpy/plotting/_tools/scatterplots.py
index 7f69a76025..4ce39f7211 100644
--- a/src/scanpy/plotting/_tools/scatterplots.py
+++ b/src/scanpy/plotting/_tools/scatterplots.py
@@ -94,7 +94,7 @@ def embedding(
     na_in_legend: bool = True,
     size: float | Sequence[float] | None = None,
     frameon: bool | None = None,
-    legend_fontsize: int | float | _FontSize | None = None,
+    legend_fontsize: float | _FontSize | None = None,
     legend_fontweight: int | _FontWeight = "bold",
     legend_loc: _LegendLoc | None = "right margin",
     legend_fontoutline: int | None = None,
diff --git a/src/scanpy/preprocessing/_scale.py b/src/scanpy/preprocessing/_scale.py
index be452c356d..a7a16bbcc4 100644
--- a/src/scanpy/preprocessing/_scale.py
+++ b/src/scanpy/preprocessing/_scale.py
@@ -148,7 +148,6 @@ def scale_array(
     | tuple[
         np.ndarray | DaskArray, NDArray[np.float64] | DaskArray, NDArray[np.float64]
     ]
-    | DaskArray
 ):
     if copy:
         X = X.copy()
diff --git a/src/scanpy/preprocessing/_scrublet/sparse_utils.py b/src/scanpy/preprocessing/_scrublet/sparse_utils.py
index b4ff1a36b0..cc0b1bc815 100644
--- a/src/scanpy/preprocessing/_scrublet/sparse_utils.py
+++ b/src/scanpy/preprocessing/_scrublet/sparse_utils.py
@@ -17,7 +17,7 @@
 
 def sparse_multiply(
     E: sparse.csr_matrix | sparse.csc_matrix | NDArray[np.float64],
-    a: float | int | NDArray[np.float64],
+    a: float | NDArray[np.float64],
 ) -> sparse.csr_matrix | sparse.csc_matrix:
     """multiply each row of E by a scalar"""
 
diff --git a/src/scanpy/tools/_marker_gene_overlap.py b/src/scanpy/tools/_marker_gene_overlap.py
index 83a19c86a4..eb07b84885 100644
--- a/src/scanpy/tools/_marker_gene_overlap.py
+++ b/src/scanpy/tools/_marker_gene_overlap.py
@@ -4,7 +4,7 @@
 
 from __future__ import annotations
 
-from collections.abc import Set
+from collections.abc import Set as AbstractSet
 from typing import TYPE_CHECKING
 
 import numpy as np
@@ -187,7 +187,7 @@ def marker_gene_overlap(
     if normalize is not None and method != "overlap_count":
         raise ValueError("Can only normalize with method=`overlap_count`.")
 
-    if not all(isinstance(val, Set) for val in reference_markers.values()):
+    if not all(isinstance(val, AbstractSet) for val in reference_markers.values()):
         try:
             reference_markers = {
                 key: set(val) for key, val in reference_markers.items()
diff --git a/src/scanpy/tools/_rank_genes_groups.py b/src/scanpy/tools/_rank_genes_groups.py
index f8ab13e9fd..9a2896196a 100644
--- a/src/scanpy/tools/_rank_genes_groups.py
+++ b/src/scanpy/tools/_rank_genes_groups.py
@@ -749,7 +749,7 @@ def filter_rank_genes_groups(
     use_raw: bool | None = None,
     key_added: str = "rank_genes_groups_filtered",
     min_in_group_fraction: float = 0.25,
-    min_fold_change: int | float = 1,
+    min_fold_change: float = 1,
     max_out_group_fraction: float = 0.5,
     compare_abs: bool = False,
 ) -> None:
diff --git a/src/scanpy/tools/_tsne.py b/src/scanpy/tools/_tsne.py
index 23d490218b..ac0e6a6317 100644
--- a/src/scanpy/tools/_tsne.py
+++ b/src/scanpy/tools/_tsne.py
@@ -34,10 +34,10 @@ def tsne(
     n_pcs: int | None = None,
     *,
     use_rep: str | None = None,
-    perplexity: float | int = 30,
+    perplexity: float = 30,
     metric: str = "euclidean",
-    early_exaggeration: float | int = 12,
-    learning_rate: float | int = 1000,
+    early_exaggeration: float = 12,
+    learning_rate: float = 1000,
     random_state: AnyRandom = 0,
     use_fast_tsne: bool = False,
     n_jobs: int | None = None,