Blocks annoying video ads on YouTube, Facebook ads, banners and much more.
Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).
Download all the links, movies and audio clips of a page at the maximum speed with a single click, using the most popular, lightweight and reliable external download managers.
Displays a country flag depicting the location of the current website's server and provides a multitude of tools such as site safety checks, whois, translation, similar sites, validation, URL shortening, and more...
Are you concerned about your privacy? Or, are you blocked from some websites by a firewall? And, are you arming yourself with a proxy? In that case, AutoProxy is designed for you! A tool to help you use your proxy automatically & efficiently.
A customizable mouse gestures extension which enables to execute various commands and user scripts with six types of gestures.
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.
United States English Spellchecker for Firefox, Thunderbird and SeaMonkey by Kevin Atkinson and Geoff Kuenning.
To enable, right-click in a multi-line text box, select "Languages", then "English (United States)".
Make any pages' search functionality available in the Search Bar (or "search box")...
Help make Firefox better. The Add-on Compatibility Reporter enables you to report if the Firefox add-ons that you're using are working properly.
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!
Download videos with comments from Nico Nico Douga and change your video-watching experience!