diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index c20b2840a40ab..c9cbc858fae29 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -231,7 +231,7 @@ class NDFrame(PandasObject, SelectionMixin, indexing.IndexingMixin):
     _metadata: List[str] = []
     _is_copy: Optional[weakref.ReferenceType[NDFrame]] = None
     _mgr: Manager
-    _attrs: Dict[Optional[Hashable], Any]
+    _attrs: Dict[Hashable, Any]
     _typ: str
 
     # ----------------------------------------------------------------------
@@ -241,7 +241,7 @@ def __init__(
         self,
         data: Manager,
         copy: bool = False,
-        attrs: Optional[Mapping[Optional[Hashable], Any]] = None,
+        attrs: Optional[Mapping[Hashable, Any]] = None,
     ):
         # copy kwarg is retained for mypy compat, is not used
 
@@ -320,7 +320,7 @@ def _as_manager(self: FrameOrSeries, typ: str) -> FrameOrSeries:
     # attrs and flags
 
     @property
-    def attrs(self) -> Dict[Optional[Hashable], Any]:
+    def attrs(self) -> Dict[Hashable, Any]:
         """
         Dictionary of global attributes of this dataset.
 
@@ -337,7 +337,7 @@ def attrs(self) -> Dict[Optional[Hashable], Any]:
         return self._attrs
 
     @attrs.setter
-    def attrs(self, value: Mapping[Optional[Hashable], Any]) -> None:
+    def attrs(self, value: Mapping[Hashable, Any]) -> None:
         self._attrs = dict(value)
 
     @final
@@ -803,7 +803,7 @@ def swapaxes(self: FrameOrSeries, axis1, axis2, copy=True) -> FrameOrSeries:
             # error: Argument 2 to "NDFrame" has incompatible type "*Generator[Index,
             # None, None]"; expected "bool" [arg-type]
             # error: Argument 2 to "NDFrame" has incompatible type "*Generator[Index,
-            # None, None]"; expected "Optional[Mapping[Optional[Hashable], Any]]"
+            # None, None]"; expected "Optional[Mapping[Hashable, Any]]"
             new_values,  # type: ignore[arg-type]
             *new_axes,  # type: ignore[arg-type]
         ).__finalize__(self, method="swapaxes")
diff --git a/pandas/io/json/_json.py b/pandas/io/json/_json.py
index 7c83beca1ae71..b7493ebeadf34 100644
--- a/pandas/io/json/_json.py
+++ b/pandas/io/json/_json.py
@@ -572,7 +572,7 @@ def read_json(
     if dtype is None and orient != "table":
         # error: Incompatible types in assignment (expression has type "bool", variable
         # has type "Union[ExtensionDtype, str, dtype[Any], Type[str], Type[float],
-        # Type[int], Type[complex], Type[bool], Type[object], Dict[Optional[Hashable],
+        # Type[int], Type[complex], Type[bool], Type[object], Dict[Hashable,
         # Union[ExtensionDtype, Union[str, dtype[Any]], Type[str], Type[float],
         # Type[int], Type[complex], Type[bool], Type[object]]], None]")
         dtype = True  # type: ignore[assignment]
@@ -921,7 +921,7 @@ def _try_convert_data(self, name, data, use_dtypes=True, convert_dates=True):
 
             # error: Non-overlapping identity check (left operand type:
             # "Union[ExtensionDtype, str, dtype[Any], Type[object],
-            # Dict[Optional[Hashable], Union[ExtensionDtype, Union[str, dtype[Any]],
+            # Dict[Hashable, Union[ExtensionDtype, Union[str, dtype[Any]],
             # Type[str], Type[float], Type[int], Type[complex], Type[bool],
             # Type[object]]]]", right operand type: "Literal[True]")
             elif self.dtype is True:  # type: ignore[comparison-overlap]
diff --git a/pandas/io/sql.py b/pandas/io/sql.py
index e3347468828d1..200565b837dea 100644
--- a/pandas/io/sql.py
+++ b/pandas/io/sql.py
@@ -1563,7 +1563,7 @@ def to_sql(
             if not is_dict_like(dtype):
                 # error: Value expression in dictionary comprehension has incompatible
                 # type "Union[ExtensionDtype, str, dtype[Any], Type[object],
-                # Dict[Optional[Hashable], Union[ExtensionDtype, Union[str, dtype[Any]],
+                # Dict[Hashable, Union[ExtensionDtype, Union[str, dtype[Any]],
                 # Type[str], Type[float], Type[int], Type[complex], Type[bool],
                 # Type[object]]]]"; expected type "Union[ExtensionDtype, str,
                 # dtype[Any], Type[object]]"
@@ -2060,7 +2060,7 @@ def to_sql(
             if not is_dict_like(dtype):
                 # error: Value expression in dictionary comprehension has incompatible
                 # type "Union[ExtensionDtype, str, dtype[Any], Type[object],
-                # Dict[Optional[Hashable], Union[ExtensionDtype, Union[str, dtype[Any]],
+                # Dict[Hashable, Union[ExtensionDtype, Union[str, dtype[Any]],
                 # Type[str], Type[float], Type[int], Type[complex], Type[bool],
                 # Type[object]]]]"; expected type "Union[ExtensionDtype, str,
                 # dtype[Any], Type[object]]"
diff --git a/pandas/plotting/_matplotlib/core.py b/pandas/plotting/_matplotlib/core.py
index b355cba6354da..b649368a80820 100644
--- a/pandas/plotting/_matplotlib/core.py
+++ b/pandas/plotting/_matplotlib/core.py
@@ -609,8 +609,8 @@ def _make_legend(self):
                         self.legend_handles
                     )
                     # error: Incompatible types in assignment (expression has type
-                    # "Iterator[Optional[Hashable]]", variable has type
-                    # "List[Optional[Hashable]]")
+                    # "Iterator[Hashable]", variable has type
+                    # "List[Hashable]")
                     self.legend_labels = reversed(  # type: ignore[assignment]
                         self.legend_labels
                     )