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).
The easy way to download and convert Web videos from hundreds of YouTube-like sites.
The first and only download manager/accelerator built inside Firefox!
MORE THAN 21 MILLION DOWNLOADS
ImTranslator provides translation powered by Google Translate, Microsoft, Babylon for 70+ languages. It includes Translator, Dictionary, Text-to-Speech, Back Translation.
Video Tutorial: http://youtu.be/qyLyFkQuMGU
If you are the kind of person who likes to have total control over every aspect of your downloads, "Download Status Bar" is the add-on you are looking for.
A customizable mouse gestures extension which enables to execute various commands and user scripts with six types of gestures.
Multiple account (or label) Gmail notifier (without storing passwords)
LeechBlock 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.
Displays tabs in tiled layouts in Firefox. Arrange tiles horizontally, vertically or in a grid. Resize tiles by dragging splitter bars. Tabs and links can be dragged to open in other tiles. Supports multiple tiled layouts. Works with tab groups.
Make your bookmarks bar better. Roomy Bookmarks Toolbar can: hide bookmarks/folders name(dock like), multirow, autohide and many another features(more than 20).
Customize your bookmarks bar using one add-on.
AddThis for Firefox is the best add-on to make sharing and bookmarking simple. Have all your favorite web 2.0 social networking, bookmarking, blogging, and e-mail services at your fingertips. Share any page, anytime, with anyone.
Make any pages' search functionality available in the Search Bar (or "search box")...
Lets you load pages in IE with a single right-click, or mark certain sites to *always* load in IE.
Collections are groups of related add-ons that anyone can create and share.Explore Collections