Download Flash and Video is a great download helper tool that lets you download Flash games and Flash videos (YouTube, Facebook, Dailymotion, Google Videos and more) with a single click.
The downloader is very easy to use.
Automate Firefox. Record and replay repetitious work. If you love the Firefox web browser, but are tired of repetitive tasks like visiting the same sites every days, filling out forms, and remembering passwords, then iMacros for Firefox is the soluti...
The most lightweight and easiest translator. Translate between more than 50 languages with one click or a hot key. Translate from one word to a whole page.
Personas are free, easy-to-install "skins" for Firefox. Personas Plus extends that built-in functionality to give you even more control and easier access to new, popular, and your own favorite Personas.
Adds links to convert and download Youtube, MyVideo, Clipfish, Sevenload, Dailymotion, MySpace videos as MP3 files. Visit our site: http://www.video2mp3.net for more information
Access to Google contacts and synchronize them with Thunderbird address books.
Multifox is an extension that allows Firefox to connect to websites using different user names. Simultaneously!
Wappalyzer is a browser extension that identifies software on websites.
Adds the Google Calendar web interface as a new tab directly into Thunderbird. Creating and viewing events works just as it would in a browser like Firefox
Help us make Firefox better by joining our structured user studies! No need to download this add-on if you are running Firefox 4 beta, - you are already a part of the team!
Automatically find user scripts on Userscripts.org (requires Greasemonkey or Scriptish)