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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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Privacy & Security extensions
Privacy & Security extensions
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Essential add-ons
Essential add-ons
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Reddit extensions
Reddit extensions
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Top rated themes
Tab managers
  • Tree Style Tab

    Tree Style Tab

    Show tabs like a tree.

    213,480 users

  • Simple Tab Groups

    Simple Tab Groups

    Create, modify, and quickly change tab groups

    101,074 users

  • OneTab

    OneTab

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

    169,649 users

  • Tab Session Manager

    Tab Session Manager

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

    143,931 users

Creativity extensions
  • Grammar and Spell Checker - LanguageTool

    Grammar and Spell Checker - LanguageTool

    With this extension you can check text with the free style and grammar checker LanguageTool. It finds many errors that a simple spell checker cannot detect, like mixing up there/their, a/an, or repeating a word.

    395,655 users

  • Search by Image

    Search by Image

    A powerful reverse image search tool, with support for various search engines, such as Google, Bing, Yandex, Baidu and TinEye.

    401,775 users

  • Dark Background and Light Text

    Dark Background and Light Text

    Make every web page (or just the pages you want) display light text on dark backgrounds. All color variations are fully customizable.

    45,581 users

  • LeechBlock NG

    LeechBlock NG

    LeechBlock NG is a simple productivity tool designed to block those time-wasting sites that can suck the life out of your working day. All you need to do is specify which sites to block and when to block them.

    109,727 users

“video downloader” tagged extensions
  • Video DownloadHelper

    Video DownloadHelper

    Download videos from the web. Easy, smart, no tracking.

    1,883,962 users

  • Easy Youtube Video Downloader Express

    Easy Youtube Video Downloader Express

    A simple extension for superfast and easy YouTube downloads in FLV, 3GP, MP3, MP4, 720p, and 1080p formats.

    488,562 users

  • Download Video and Flash - HD Download

    Download Video and Flash - HD Download

    Download Video and Flash - HD Download is a great download helper tool that lets you download video and Flash games very easily. Download from YouTube, Facebook, Dailymotion, Vimeo and more. Download and enjoy! Download now!

    60,955 users

  • YouTube Downloader (UDL Helper)

    YouTube Downloader (UDL Helper)

    Download YouTube / Instagram / Odnoklassniki videos and extract audio from video with just a few mouse clicks. Supported media formats are MP3, MP4, WEBM. Capture frames from online videos with a screenshot button.

    36,428 users