diff --git a/pyproject.toml b/pyproject.toml
index bdb635f..d593f56 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -18,6 +18,7 @@ dependencies = [
 [project.optional-dependencies]
 dev = [
     "mypy>=1.0.0",
+    "types-requests>=2.31.0",
 ]
 
 [project.scripts]
diff --git a/src/app.py b/src/app.py
index 0b6e0c2..43a29d1 100644
--- a/src/app.py
+++ b/src/app.py
@@ -6,6 +6,7 @@ from textual.command import Provider, Hit
 from rich.markup import escape
 from pathlib import Path
 from functools import partial
+from typing import TYPE_CHECKING, cast, Any
 import threading
 import logging
 
@@ -43,7 +44,7 @@ class CacheCommandProvider(Provider):
                 yield Hit(
                     score,
                     matcher.highlight(display_name),
-                    partial(self.app.action_cache_command, command_name),
+                    partial(cast('MomaApp', self.app).action_cache_command, command_name),
                     help=help_text
                 )
 
@@ -208,11 +209,11 @@ class MomaApp(App):
 
         # File type icons
         icons = {
-            'mkv': '󰈫',   # Video camera for MKV
-            'mk3d': '󰟽',  # Clapper board for 3D
-            'mp4': '󰎁',   # Video camera
-            'mov': '󰎁',   # Video camera
-            'webm': '',  # Video camera
+            'mkv': '🎥',   # Video camera for MKV
+            'mk3d': '🕹️',  # Clapper board for 3D
+            'mp4': '🎥',   # Video camera
+            'mov': '🎥',   # Video camera
+            'webm': '🎥',  # Video camera
             'avi': '💿',   # Film frames for AVI
             'wmv': '📀',   # Video camera
             'm4v': '📹',   # Video camera
@@ -308,14 +309,12 @@ class MomaApp(App):
             extractor = MediaExtractor(file_path)
 
             mode = self.settings.get("mode")
-            poster_content = ""
+            poster_content: Any = ""
 
             if mode == "technical":
-                formatter = MediaPanelView(extractor)
-                full_info = formatter.file_info_panel()
+                full_info = MediaPanelView(extractor).file_info_panel()
             else:  # catalog
-                formatter = CatalogFormatter(extractor, self.settings)
-                full_info, poster_content = formatter.format_catalog_info()
+                full_info, poster_content = CatalogFormatter(extractor, self.settings).format_catalog_info()
 
             # Update UI
             self.call_later(
diff --git a/src/cache/core.py b/src/cache/core.py
index 7290673..1538fc1 100644
--- a/src/cache/core.py
+++ b/src/cache/core.py
@@ -16,6 +16,7 @@ class Cache:
 
     _instance: Optional['Cache'] = None
     _lock_init = threading.Lock()
+    _initialized: bool
 
     def __new__(cls, cache_dir: Optional[Path] = None):
         """Create or return singleton instance."""
diff --git a/src/constants/__init__.py b/src/constants/__init__.py
index dc92ccb..c6d1b56 100644
--- a/src/constants/__init__.py
+++ b/src/constants/__init__.py
@@ -18,7 +18,7 @@ from .media_constants import (
     get_extension_from_format
 )
 from .source_constants import SOURCE_DICT
-from .frame_constants import FRAME_CLASSES, NON_STANDARD_QUALITY_INDICATORS
+from .frame_constants import FRAME_CLASSES, NON_STANDARD_QUALITY_INDICATORS, FrameClassInfo
 from .moviedb_constants import MOVIE_DB_DICT
 from .edition_constants import SPECIAL_EDITIONS
 from .lang_constants import SKIP_WORDS
@@ -35,6 +35,7 @@ __all__ = [
     # Frame classes
     'FRAME_CLASSES',
     'NON_STANDARD_QUALITY_INDICATORS',
+    'FrameClassInfo',
     # Movie databases
     'MOVIE_DB_DICT',
     # Special editions
diff --git a/src/constants/frame_constants.py b/src/constants/frame_constants.py
index aeb899a..89e085e 100644
--- a/src/constants/frame_constants.py
+++ b/src/constants/frame_constants.py
@@ -7,6 +7,15 @@ Also includes non-standard quality indicators that appear in filenames but don't
 represent specific resolutions.
 """
 
+from typing import TypedDict
+
+
+class FrameClassInfo(TypedDict):
+    """Information about a video frame class."""
+    nominal_height: int
+    typical_widths: list[int]
+    description: str
+
 # Non-standard quality indicators that don't have specific resolution values
 # These are used in filenames to indicate quality but aren't proper frame classes
 # When found, we return None instead of trying to classify them
@@ -15,7 +24,7 @@ represent specific resolutions.
 # the exact resolution, so we treat them as non-standard indicators
 NON_STANDARD_QUALITY_INDICATORS = ['SD', 'LQ', 'HD', 'QHD', 'FHD', 'FullHD', '4K', '8K']
 
-FRAME_CLASSES = {
+FRAME_CLASSES: dict[str, FrameClassInfo] = {
     "480p": {
         "nominal_height": 480,
         "typical_widths": [640, 704, 720],
diff --git a/src/constants/media_constants.py b/src/constants/media_constants.py
index 99d9908..493138e 100644
--- a/src/constants/media_constants.py
+++ b/src/constants/media_constants.py
@@ -87,7 +87,7 @@ MEDIA_TYPES = {
 
 # Reverse mapping: meta_type -> list of extensions
 # Built once at module load instead of rebuilding in every extractor instance
-META_TYPE_TO_EXTENSIONS = {}
+META_TYPE_TO_EXTENSIONS: dict[str, list[str]] = {}
 for ext, info in MEDIA_TYPES.items():
     meta_type = info.get('meta_type')
     if meta_type:
diff --git a/src/extractors/mediainfo_extractor.py b/src/extractors/mediainfo_extractor.py
index 71d50a4..52f3e18 100644
--- a/src/extractors/mediainfo_extractor.py
+++ b/src/extractors/mediainfo_extractor.py
@@ -1,6 +1,7 @@
 from pathlib import Path
 from pymediainfo import MediaInfo
 from collections import Counter
+from typing import Any
 from ..constants import FRAME_CLASSES, get_extension_from_format
 from ..cache import cached_method, Cache
 import langcodes
@@ -52,7 +53,7 @@ class MediaInfoExtractor:
             Cache() if use_cache else None
         )  # Singleton cache for @cached_method decorator
         self.settings = None  # Will be set by Settings singleton if needed
-        self._cache = {}  # Internal cache for method results
+        self._cache: dict[str, Any] = {}  # Internal cache for method results
 
     @cached_method()
     def _get_media_info(self) -> MediaInfo | None:
diff --git a/src/extractors/tmdb_extractor.py b/src/extractors/tmdb_extractor.py
index 3fd72bf..4c753db 100644
--- a/src/extractors/tmdb_extractor.py
+++ b/src/extractors/tmdb_extractor.py
@@ -1,7 +1,3 @@
-import json
-import os
-import time
-import hashlib
 import requests
 import logging
 from pathlib import Path
@@ -17,7 +13,7 @@ class TMDBExtractor:
         self.cache = Cache() if use_cache else None  # Singleton cache
         self.settings = Settings()  # Singleton settings
         self.ttl_seconds = self.settings.get("cache_ttl_extractors", 21600)
-        self._movie_db_info = None
+        self._movie_db_info: Optional[Dict[str, Any]] = None
 
     def _get_cached_data(self, cache_key: str) -> Optional[Dict[str, Any]]:
         """Get data from cache if valid"""
@@ -301,5 +297,5 @@ class TMDBExtractor:
             local_path = self.cache.set_image(cache_key, image_data, self.ttl_seconds)
             return str(local_path) if local_path else None
         except requests.RequestException as e:
-            logging.warning(f"Failed to download poster from {poster_url}: {e}")
+            logging.warning(f"Failed to download poster from {url}: {e}")
             return None
diff --git a/src/formatters/base.py b/src/formatters/base.py
index c24dd1d..f202907 100644
--- a/src/formatters/base.py
+++ b/src/formatters/base.py
@@ -5,7 +5,7 @@ should inherit from. This ensures a consistent interface and enables type checki
 """
 
 from abc import ABC, abstractmethod
-from typing import Any
+from typing import Any, Callable
 
 
 class Formatter(ABC):
@@ -106,7 +106,7 @@ class MarkupFormatter(Formatter):
     pass
 
 
-class CompositeFormatter(Formatter):
+class CompositeFormatter:
     """Formatter that applies multiple formatters in sequence.
 
     This class allows chaining multiple formatters together in a specific order.
@@ -122,7 +122,7 @@ class CompositeFormatter(Formatter):
         formatters: List of formatter functions to apply in order
     """
 
-    def __init__(self, formatters: list[callable]):
+    def __init__(self, formatters: list[Callable[..., Any]]):
         """Initialize the composite formatter.
 
         Args:
diff --git a/src/formatters/catalog_formatter.py b/src/formatters/catalog_formatter.py
index 498e969..5c8380c 100644
--- a/src/formatters/catalog_formatter.py
+++ b/src/formatters/catalog_formatter.py
@@ -1,6 +1,7 @@
 from .text_formatter import TextFormatter
 from src.views.posters import AsciiPosterRenderer, ViuPosterRenderer, RichPixelsPosterRenderer
-from typing import Union
+from typing import Union, Any
+from io import StringIO
 import os
 
 
@@ -11,7 +12,7 @@ class CatalogFormatter:
         self.extractor = extractor
         self.settings = settings
 
-    def format_catalog_info(self) -> tuple[str, Union[str, object]]:
+    def format_catalog_info(self) -> tuple[str, Any]:
         """Format catalog information for display.
 
         Returns:
@@ -66,18 +67,18 @@ class CatalogFormatter:
         text_content = "\n\n".join(lines) if lines else "No catalog information available"
 
         from rich.console import Console
-        from io import StringIO
 
-        console = Console(file=StringIO(), width=120, legacy_windows=False)
+        sio = StringIO()
+        console = Console(file=sio, width=120, legacy_windows=False)
         console.print(text_content, markup=True)
-        rendered_text = console.file.getvalue()
+        rendered_text = sio.getvalue()
 
         # Get poster separately
         poster_content = self.get_poster()
 
         return rendered_text, poster_content
 
-    def get_poster(self) -> Union[str, object]:
+    def get_poster(self) -> Any:
         """Get poster content for separate display.
 
         Returns:
@@ -99,7 +100,7 @@ class CatalogFormatter:
                 return f"{TextFormatter.bold('Poster:')} {poster_path} (not cached yet)"
             return ""
 
-    def _display_poster(self, image_path: str, mode: str) -> Union[str, object]:
+    def _display_poster(self, image_path: str, mode: str) -> Any:
         """Display poster image based on mode setting.
 
         Args:
@@ -113,6 +114,7 @@ class CatalogFormatter:
             return f"Image file not found: {image_path}"
 
         # Select renderer based on mode
+        renderer: Union[ViuPosterRenderer, AsciiPosterRenderer, RichPixelsPosterRenderer]
         if mode == "viu":
             renderer = ViuPosterRenderer()
         elif mode == "pseudo":
diff --git a/src/formatters/size_formatter.py b/src/formatters/size_formatter.py
index e364821..3bcdf3c 100644
--- a/src/formatters/size_formatter.py
+++ b/src/formatters/size_formatter.py
@@ -4,11 +4,12 @@ class SizeFormatter:
     @staticmethod
     def format_size(bytes_size: int) -> str:
         """Format bytes to human readable with unit"""
+        size: float = bytes_size
         for unit in ['B', 'KB', 'MB', 'GB', 'TB']:
-            if bytes_size < 1024:
-                return f"{bytes_size:.1f} {unit}"
-            bytes_size /= 1024
-        return f"{bytes_size:.1f} TB"
+            if size < 1024:
+                return f"{size:.1f} {unit}"
+            size /= 1024
+        return f"{size:.1f} TB"
 
     @staticmethod
     def format_size_full(bytes_size: int) -> str:
diff --git a/src/services/conversion_service.py b/src/services/conversion_service.py
index e284761..b78f996 100644
--- a/src/services/conversion_service.py
+++ b/src/services/conversion_service.py
@@ -287,7 +287,7 @@ class ConversionService:
         logger.debug(f"Expanded languages from '{audio_langs_str}' to: {langs}")
 
         # Map to tracks (pad with None if needed)
-        result = []
+        result: List[Optional[str]] = []
         for i in range(audio_track_count):
             if i < len(langs):
                 result.append(langs[i])
diff --git a/src/services/metadata_service.py b/src/services/metadata_service.py
index 6096a1f..c330a1c 100644
--- a/src/services/metadata_service.py
+++ b/src/services/metadata_service.py
@@ -9,7 +9,7 @@ This service manages the extraction of metadata from media files with:
 
 import logging
 from pathlib import Path
-from typing import Optional, Callable
+from typing import Optional, Callable, Any
 from concurrent.futures import ThreadPoolExecutor, Future
 from threading import Lock
 
@@ -169,12 +169,11 @@ class MetadataService:
             mode = self.settings.get("mode")
 
             # Format based on mode
+            formatted_info: Any
             if mode == "technical":
-                formatter = MediaPanelView(extractor)
-                formatted_info = formatter.file_info_panel()
+                formatted_info = MediaPanelView(extractor).file_info_panel()
             else:  # catalog
-                formatter = CatalogFormatter(extractor, self.settings)
-                formatted_info = formatter.format_catalog_info()
+                formatted_info = CatalogFormatter(extractor, self.settings).format_catalog_info()
 
             # Generate proposed name
             proposed_formatter = ProposedFilenameView(extractor)
diff --git a/src/services/rename_service.py b/src/services/rename_service.py
index 1449929..308b128 100644
--- a/src/services/rename_service.py
+++ b/src/services/rename_service.py
@@ -247,13 +247,13 @@ class RenameService:
         is_valid, error = self.validate_filename(sanitized_filename)
         if not is_valid:
             logger.error(f"Invalid filename: {error}")
-            return False, error
+            return False, error or "Invalid filename"
 
         # Check for conflicts
         has_conflict, conflict_msg = self.check_name_conflict(source_path, sanitized_filename)
         if has_conflict:
             logger.warning(f"Name conflict: {conflict_msg}")
-            return False, conflict_msg
+            return False, conflict_msg or "Name conflict"
 
         # Build the new path
         new_path = source_path.parent / sanitized_filename
diff --git a/src/settings.py b/src/settings.py
index 3415d6c..f05eacb 100644
--- a/src/settings.py
+++ b/src/settings.py
@@ -22,6 +22,7 @@ class Settings:
 
     _instance: Optional['Settings'] = None
     _lock = threading.Lock()
+    _initialized: bool
 
     def __new__(cls, config_dir: Path | None = None):
         """Create or return singleton instance."""
diff --git a/src/views/media_panel_properties.py b/src/views/media_panel_properties.py
index 148ff77..c1e4848 100644
--- a/src/views/media_panel_properties.py
+++ b/src/views/media_panel_properties.py
@@ -540,3 +540,4 @@ class MediaPanelProperties:
     @track_decorators.subtitle_track()
     def subtitle_track(self, track, index) -> str:
         """Get subtitle track info formatted with label."""
+        return track
diff --git a/src/views/posters/ascii_renderer.py b/src/views/posters/ascii_renderer.py
index 9060029..8c5b8e4 100644
--- a/src/views/posters/ascii_renderer.py
+++ b/src/views/posters/ascii_renderer.py
@@ -1,12 +1,13 @@
 """ASCII art poster renderer."""
 
 from .base import PosterRenderer
+from typing import Any
 
 
 class AsciiPosterRenderer(PosterRenderer):
     """Render posters as ASCII art using PIL."""
 
-    def render(self, image_path: str, width: int = 35) -> str:
+    def render(self, image_path: str, width: int = 35) -> Any:
         """Render poster as ASCII art.
 
         Args:
@@ -28,7 +29,7 @@ class AsciiPosterRenderer(PosterRenderer):
             from PIL import Image, ImageEnhance
 
             # Open image
-            img = Image.open(image_path)
+            img: Any = Image.open(image_path)
 
             # Enhance contrast for better detail
             enhancer = ImageEnhance.Contrast(img)
@@ -57,7 +58,7 @@ class AsciiPosterRenderer(PosterRenderer):
 
                     # Map pixel brightness to character
                     # Invert: 0 (black) -> dark char, 255 (white) -> light char
-                    char_index = (255 - avg) * (len(ascii_chars) - 1) // 255
+                    char_index = int((255 - avg) * (len(ascii_chars) - 1) // 255)
                     char = ascii_chars[char_index]
                     row.append(char)
                 ascii_art.append(''.join(row))
diff --git a/src/views/posters/base.py b/src/views/posters/base.py
index d5d7f87..cd33016 100644
--- a/src/views/posters/base.py
+++ b/src/views/posters/base.py
@@ -1,6 +1,7 @@
 """Base class for poster renderers."""
 
 from abc import ABC, abstractmethod
+from typing import Any
 import os
 
 
@@ -8,15 +9,15 @@ class PosterRenderer(ABC):
     """Abstract base class for poster rendering implementations."""
 
     @abstractmethod
-    def render(self, image_path: str, width: int = 40) -> str:
-        """Render a poster image to a string.
+    def render(self, image_path: str, width: int = 40) -> Any:
+        """Render a poster image.
 
         Args:
             image_path: Path to the poster image file
             width: Desired width in characters
 
         Returns:
-            Rendered poster as a string
+            Rendered poster as a string or Rich Renderable
         """
         pass
 
diff --git a/src/views/posters/richpixels_renderer.py b/src/views/posters/richpixels_renderer.py
index 4b2450b..b1bae20 100644
--- a/src/views/posters/richpixels_renderer.py
+++ b/src/views/posters/richpixels_renderer.py
@@ -1,13 +1,13 @@
 """Rich-pixels renderer for high-quality terminal image display."""
 
 from .base import PosterRenderer
-from typing import Union
+from typing import Any
 
 
 class RichPixelsPosterRenderer(PosterRenderer):
     """Render posters using rich-pixels library for high-quality display."""
 
-    def render(self, image_path: str, width: int = 40) -> Union[str, object]:
+    def render(self, image_path: str, width: int = 40) -> Any:
         """Render poster using rich-pixels.
 
         Args:
diff --git a/uv.lock b/uv.lock
index ed8265f..50de46a 100644
--- a/uv.lock
+++ b/uv.lock
@@ -224,6 +224,7 @@ dependencies = [
 [package.optional-dependencies]
 dev = [
     { name = "mypy" },
+    { name = "types-requests" },
 ]
 
 [package.metadata]
@@ -237,6 +238,7 @@ requires-dist = [
     { name = "requests", specifier = ">=2.31.0" },
     { name = "rich-pixels", specifier = ">=1.0.0" },
     { name = "textual", specifier = ">=6.11.0" },
+    { name = "types-requests", marker = "extra == 'dev'", specifier = ">=2.31.0" },
 ]
 provides-extras = ["dev"]
 
@@ -501,6 +503,18 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/b5/fc/5e2988590ff2e0128eea6446806c904445a44e17256c67141573ea16b5a5/textual-6.11.0-py3-none-any.whl", hash = "sha256:9e663b73ed37123a9b13c16a0c85e09ef917a4cfded97814361ed5cccfa40f89", size = 714886, upload-time = "2025-12-18T10:48:36.269Z" },
 ]
 
+[[package]]
+name = "types-requests"
+version = "2.33.0.20260408"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "urllib3" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/69/6a/749dc53a54a3f35842c1f8197b3ca6b54af6d7458a1bfc75f6629b6da666/types_requests-2.33.0.20260408.tar.gz", hash = "sha256:95b9a86376807a216b2fb412b47617b202091c3ea7c078f47cc358d5528ccb7b", size = 23882, upload-time = "2026-04-08T04:34:49.33Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/90/b8/78fd6c037de4788c040fdd323b3369804400351b7827473920f6c1d03c10/types_requests-2.33.0.20260408-py3-none-any.whl", hash = "sha256:81f31d5ea4acb39f03be7bc8bed569ba6d5a9c5d97e89f45ac43d819b68ca50f", size = 20739, upload-time = "2026-04-08T04:34:48.325Z" },
+]
+
 [[package]]
 name = "typing-extensions"
 version = "4.15.0"