diff --git a/mypy.ini b/mypy.ini
index 49d6f61b29..4d2f566fa3 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -2,7 +2,6 @@
 follow_imports = silent
 ignore_missing_imports = True
 allow_untyped_globals = True
-exclude = tests
 plugins =
     mypy_django_plugin.main,
     mypy_drf_plugin.main
@@ -11,8 +10,53 @@ files =
     openedx/core/djangoapps/content_staging,
     openedx/core/djangoapps/content_libraries,
     openedx/core/djangoapps/xblock,
-    openedx/core/types
+    openedx/core/types,
+    openedx/core/djangoapps/content_tagging
 
 [mypy.plugins.django-stubs]
 # content_staging only works with CMS; others work with either, so we run mypy with CMS settings.
 django_settings_module = "cms.envs.test"
+
+# Selectively ignore packages known to be lacking type hints
+[mypy-bridgekeeper.*]
+ignore_missing_imports = True
+[mypy-celery.*]
+ignore_missing_imports = True
+[mypy-celery_utils.*]
+ignore_missing_imports = True
+[mypy-completion.*]
+ignore_missing_imports = True
+[mypy-crum.*]
+ignore_missing_imports = True
+[mypy-ddt.*]
+ignore_missing_imports = True
+[mypy-edx_api_doc_tools.*]
+ignore_missing_imports = True
+[mypy-edx_django_utils.*]
+ignore_missing_imports = True
+[mypy-edx_proctoring.*]
+ignore_missing_imports = True
+[mypy-edx_rest_api_client.*]
+ignore_missing_imports = True
+[mypy-edx_rest_framework_extensions.*]
+ignore_missing_imports = True
+[mypy-eventtracking.*]
+ignore_missing_imports = True
+[mypy-fs.*]
+ignore_missing_imports = True
+[mypy-model_utils.*]
+ignore_missing_imports = True
+[mypy-openedx_events.*]
+ignore_missing_imports = True
+[mypy-organizations.*]
+ignore_missing_imports = True
+[mypy-search.*]
+ignore_missing_imports = True
+[mypy-rules.*]
+ignore_missing_imports = True
+[mypy-web_fragments.*]
+ignore_missing_imports = True
+[mypy-webob.*]
+ignore_missing_imports = True
+[mypy-xblock.*]
+ignore_missing_imports = True
diff --git a/openedx/core/djangoapps/content_libraries/tests/test_runtime.py b/openedx/core/djangoapps/content_libraries/tests/test_runtime.py
index fefe1536a2..f166cee546 100644
--- a/openedx/core/djangoapps/content_libraries/tests/test_runtime.py
+++ b/openedx/core/djangoapps/content_libraries/tests/test_runtime.py
@@ -546,14 +546,14 @@ class ContentLibraryXBlockUserStateTestMixin(ContentLibraryContentTestMixin):
 
 
 @requires_blockstore
-class ContentLibraryXBlockUserStateBServiceTest(ContentLibraryXBlockUserStateTestMixin, TestCase):
+class ContentLibraryXBlockUserStateBServiceTest(ContentLibraryXBlockUserStateTestMixin, TestCase):  # type: ignore[misc]
     """
     Tests XBlock user state for XBlocks in a content library using the standalone Blockstore service.
     """
 
 
 @requires_blockstore_app
-class ContentLibraryXBlockUserStateTest(
+class ContentLibraryXBlockUserStateTest(  # type: ignore[misc]
     ContentLibraryXBlockUserStateTestMixin,
     BlockstoreAppTestMixin,
     LiveServerTestCase,
diff --git a/openedx/core/djangoapps/content_staging/tests/test_clipboard.py b/openedx/core/djangoapps/content_staging/tests/test_clipboard.py
index bc351b6b95..00c4466b7d 100644
--- a/openedx/core/djangoapps/content_staging/tests/test_clipboard.py
+++ b/openedx/core/djangoapps/content_staging/tests/test_clipboard.py
@@ -364,7 +364,7 @@ class ClipboardTestCase(ModuleStoreTestCase):
         response = nonstaff_client.get(olx_url)
         assert response.status_code == 403
 
-    def assertXmlEqual(self, xml_str_a: str, xml_str_b: str) -> bool:
+    def assertXmlEqual(self, xml_str_a: str, xml_str_b: str):
         """ Assert that the given XML strings are equal, ignoring attribute order and some whitespace variations. """
         a = ElementTree.canonicalize(xml_str_a, strip_text=True)
         b = ElementTree.canonicalize(xml_str_b, strip_text=True)
diff --git a/openedx/core/djangoapps/content_tagging/api.py b/openedx/core/djangoapps/content_tagging/api.py
index 4867160c1b..18cf2650e0 100644
--- a/openedx/core/djangoapps/content_tagging/api.py
+++ b/openedx/core/djangoapps/content_tagging/api.py
@@ -16,7 +16,7 @@ from .types import ContentKey
 
 def create_taxonomy(
     name: str,
-    description: str = None,
+    description: str | None = None,
     enabled=True,
     allow_multiple=False,
     allow_free_text=False,
@@ -36,7 +36,7 @@ def create_taxonomy(
 def set_taxonomy_orgs(
     taxonomy: Taxonomy,
     all_orgs=False,
-    orgs: list[Organization] = None,
+    orgs: list[Organization] | None = None,
     relationship: TaxonomyOrg.RelType = TaxonomyOrg.RelType.OWNER,
 ):
     """
@@ -102,7 +102,7 @@ def get_taxonomies_for_org(
 
 def get_content_tags(
     object_key: ContentKey,
-    taxonomy_id: str | None = None,
+    taxonomy_id: int | None = None,
 ) -> Iterator[ContentObjectTag]:
     """
     Generates a list of content tags for a given object.
@@ -120,7 +120,7 @@ def tag_content_object(
     object_key: ContentKey,
     taxonomy: Taxonomy,
     tags: list,
-) -> list[ContentObjectTag]:
+) -> Iterator[ContentObjectTag]:
     """
     This is the main API to use when you want to add/update/delete tags from a content object (e.g. an XBlock or
     course).
@@ -138,7 +138,7 @@ def tag_content_object(
     """
     if not taxonomy.system_defined:
         # We require that this taxonomy is linked to the content object's "org" or linked to "all orgs" (None):
-        org_short_name = object_key.org
+        org_short_name = object_key.org  # type: ignore
         if not taxonomy.taxonomyorg_set.filter(Q(org__short_name=org_short_name) | Q(org=None)).exists():
             raise ValueError(f"The specified Taxonomy is not enabled for the content object's org ({org_short_name})")
     oel_tagging.tag_object(
@@ -147,7 +147,7 @@ def tag_content_object(
         object_id=str(object_key),
         object_tag_class=ContentObjectTag,
     )
-    return get_content_tags(str(object_key), taxonomy_id=taxonomy.id)
+    return get_content_tags(object_key, taxonomy_id=taxonomy.id)
 
 
 # Expose the oel_tagging APIs
diff --git a/openedx/core/djangoapps/content_tagging/rest_api/v1/serializers.py b/openedx/core/djangoapps/content_tagging/rest_api/v1/serializers.py
index 1771816a14..0a7ff92409 100644
--- a/openedx/core/djangoapps/content_tagging/rest_api/v1/serializers.py
+++ b/openedx/core/djangoapps/content_tagging/rest_api/v1/serializers.py
@@ -2,7 +2,7 @@
 API Serializers for content tagging org
 """
 
-from rest_framework import serializers
+from rest_framework import serializers, fields
 
 from openedx_tagging.core.tagging.rest_api.v1.serializers import (
     TaxonomyListQueryParamsSerializer,
@@ -16,7 +16,7 @@ class TaxonomyOrgListQueryParamsSerializer(TaxonomyListQueryParamsSerializer):
     Serializer for the query params for the GET view
     """
 
-    org = serializers.SlugRelatedField(
+    org: fields.Field = serializers.SlugRelatedField(
         slug_field="short_name",
         queryset=Organization.objects.all(),
         required=False,
diff --git a/openedx/core/djangoapps/content_tagging/rest_api/v1/tests/test_views.py b/openedx/core/djangoapps/content_tagging/rest_api/v1/tests/test_views.py
index 8cb4b94fd2..5849f4e830 100644
--- a/openedx/core/djangoapps/content_tagging/rest_api/v1/tests/test_views.py
+++ b/openedx/core/djangoapps/content_tagging/rest_api/v1/tests/test_views.py
@@ -6,7 +6,7 @@ from urllib.parse import parse_qs, urlparse
 
 import ddt
 from django.contrib.auth import get_user_model
-from django.test.testcases import override_settings
+from django.test import override_settings
 from opaque_keys.edx.locator import BlockUsageLocator, CourseLocator
 from openedx_tagging.core.tagging.models import Tag, Taxonomy
 from openedx_tagging.core.tagging.models.system_defined import SystemDefinedTaxonomy
diff --git a/openedx/core/djangoapps/content_tagging/tasks.py b/openedx/core/djangoapps/content_tagging/tasks.py
index f28b6d156d..063a24072e 100644
--- a/openedx/core/djangoapps/content_tagging/tasks.py
+++ b/openedx/core/djangoapps/content_tagging/tasks.py
@@ -35,7 +35,7 @@ def _set_initial_language_tag(content_key: ContentKey, lang_code: str) -> None:
     """
     lang_taxonomy = Taxonomy.objects.get(pk=LANGUAGE_TAXONOMY_ID).cast()
 
-    if lang_code and not api.get_content_tags(object_key=content_key, taxonomy_id=lang_taxonomy.id).exists():
+    if lang_code and not api.get_content_tags(object_key=content_key, taxonomy_id=lang_taxonomy.id):
         try:
             lang_tag = lang_taxonomy.tag_for_external_id(lang_code)
         except api.oel_tagging.TagDoesNotExist:
diff --git a/openedx/core/djangoapps/content_tagging/tests/test_rules.py b/openedx/core/djangoapps/content_tagging/tests/test_rules.py
index 013b822558..4edb43b28b 100644
--- a/openedx/core/djangoapps/content_tagging/tests/test_rules.py
+++ b/openedx/core/djangoapps/content_tagging/tests/test_rules.py
@@ -2,7 +2,7 @@
 
 import ddt
 from django.contrib.auth import get_user_model
-from django.test.testcases import TestCase, override_settings
+from django.test import TestCase, override_settings
 from opaque_keys.edx.locator import BlockUsageLocator, CourseLocator
 from openedx_tagging.core.tagging.models import (
     Tag,
diff --git a/openedx/core/djangoapps/content_tagging/tests/test_tasks.py b/openedx/core/djangoapps/content_tagging/tests/test_tasks.py
index 39e1742b9e..fccac3e307 100644
--- a/openedx/core/djangoapps/content_tagging/tests/test_tasks.py
+++ b/openedx/core/djangoapps/content_tagging/tests/test_tasks.py
@@ -51,7 +51,7 @@ class LanguageTaxonomyTestMixin:
 
 @skip_unless_cms  # Auto-tagging is only available in the CMS
 @override_waffle_flag(CONTENT_TAGGING_AUTO, active=True)
-class TestAutoTagging(LanguageTaxonomyTestMixin, ModuleStoreTestCase):
+class TestAutoTagging(LanguageTaxonomyTestMixin, ModuleStoreTestCase):  # type: ignore[misc]
     """
     Test if the Course and XBlock tags are automatically created
     """
@@ -64,7 +64,7 @@ class TestAutoTagging(LanguageTaxonomyTestMixin, ModuleStoreTestCase):
 
         If value is None, check if the ObjectTag does not exists
         """
-        object_tags = api.get_content_tags(object_key, taxonomy_id=taxonomy_id)
+        object_tags = list(api.get_content_tags(object_key, taxonomy_id=taxonomy_id))
         object_tag = object_tags[0] if len(object_tags) == 1 else None
         if len(object_tags) > 1:
             raise ValueError("Found too many object tags")
diff --git a/openedx/core/djangoapps/xblock/tests/test_utils.py b/openedx/core/djangoapps/xblock/tests/test_utils.py
index c8181165c7..229406e1bc 100644
--- a/openedx/core/djangoapps/xblock/tests/test_utils.py
+++ b/openedx/core/djangoapps/xblock/tests/test_utils.py
@@ -136,6 +136,7 @@ def test_secure_token(param_delta: dict, expected_validation: bool):
         SECRET_KEY=params["generation_secret_key"],
         XBLOCK_HANDLER_TOKEN_KEYS=params["generation_xblock_handler_token_keys"],
     ):
+        assert isinstance(reference_time, datetime.datetime)
         with freeze_time(reference_time):
             token = get_secure_token_for_xblock_handler(
                 params["generation_user_id"], params["generation_block_key_str"]
@@ -145,7 +146,9 @@ def test_secure_token(param_delta: dict, expected_validation: bool):
         SECRET_KEY=params["validation_secret_key"],
         XBLOCK_HANDLER_TOKEN_KEYS=params["validation_xblock_handler_token_keys"],
     ):
-        with freeze_time(reference_time + datetime.timedelta(seconds=params["validation_time_delta_s"])):
+        assert isinstance(params["validation_time_delta_s"], int)
+        new_reference_time = reference_time + datetime.timedelta(seconds=float(params["validation_time_delta_s"]))
+        with freeze_time(new_reference_time):
             assert (
                 validate_secure_token_for_xblock_handler(
                     params["validation_user_id"], params["validation_block_key_str"], token