To use these add-ons, you'll need to download Firefox.

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Power Thesaurus

Pack a powerful thesaurus right inside Firefox.
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Extensions are like apps for Firefox.

They add features to Firefox to make browsing faster, safer, or just plain fun.
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2025 Staff Picks
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Extension Starter Pack
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Tab managers
  • OneTab

    OneTab

    OneTab - Too many tabs? Convert tabs to a list and reduce browser memory

    162,345 users

  • Tree Style Tab

    Tree Style Tab

    Show tabs like a tree.

    166,352 users

  • Tab Session Manager

    Tab Session Manager

    Save and restore the state of windows and tabs. It also supports automatic saving and cloud sync.

    149,598 users

  • Auto Tab Discard

    Auto Tab Discard

    Increase browser speed and reduce memory load and when you have numerous open tabs.

    76,001 users

Social media extensions
  • Return YouTube Dislike

    Return YouTube Dislike

    Returns ability to see dislike statistics on youtube

    910,047 users

  • BetterTTV

    BetterTTV

    Enhances Twitch and YouTube with new features, emotes, and more.

    492,022 users

  • Sink It for Reddit

    Sink It for Reddit

    Upgrade your Reddit experience with color coded comments, easier nav, sub-reddit blocking, gestures for upvoting, ad+nag blocking, and more. It's like RES, for mobile!

    11,914 users

  • Control Panel for Twitter

    Control Panel for Twitter

    Gives you more control over Twitter and adds missing features and UI improvements

    44,912 users

Accessibility extensions
  • Dark Reader

    Dark Reader

    Dark mode for every website. Take care of your eyes, use dark theme for night and daily browsing.

    1,275,163 users

  • Read Aloud: A Text to Speech Voice Reader

    Read Aloud: A Text to Speech Voice Reader

    Read out loud the current web-page article with one click. Supports 40+ languages.

    201,272 users

  • Dark Mode

    Dark Mode

    Dark theme and night shift mode for every website. Care your eyes, use Dark Mode for night and daily web browsing.

    45,448 users

  • Sidebery

    Sidebery

    Vertical tabs tree and bookmarks in sidebar with advanced containers configuration, grouping and many other features.

    57,817 users

“dark mode” tagged extensions
  • Dark Reader

    Dark Reader

    Dark mode for every website. Take care of your eyes, use dark theme for night and daily browsing.

    1,275,163 users

  • 'Improve YouTube!'  🎧 (For YouTube & Video)

    'Improve YouTube!' 🎧 (For YouTube & Video)

    Youtube Extension. Powerful but lightweight. Enrich your Youtube and content selection. Make YouTube tidy and smart! (Layout, Filters, Shortcuts, Playlist)

    106,400 users

  • Block Site

    Block Site

    A customizable, password-protected website blocker and redirector.

    70,841 users

  • Turn Off the Lights for Firefox

    Turn Off the Lights for Firefox

    The entire page will be fading to dark, so you can watch the videos as if you were in the cinema. Works for YouTube and Beyond. Dark mode for all websites. It works for all known video sites such as YouTube, Vimeo, Twitch, Dailymotion, Facebook, etc.

    45,618 users