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).
Collector's Note block ads, e.g., on facebook
Xmarks is the #1 bookmarking and open tab add-on. Keep your bookmarks, and open tabs backed up and synchronized across computers and browsers. Mobile phones with Premium access. Utilize LastPass to sync passwords!
A customizable mouse gestures extension which enables to execute various commands and user scripts with six types of gestures.
(former Google Dictionary and Google Translate)
In-line dictionary for any word you point to or double-click; whole page translation of any web page in another language.
A very simple tabbed browsing extension that loads your homepage when you open a new tab. If you have multiple homepages, the first is chosen.
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.
"Maximize your screen space by controlling the presence of Firefox window Title-bar (Caption) & borders!", to be like Chrome Browser. - Hide FF's caption with 'smart' options, *optional* custom caption & resizers. - Works with ChromiFox-like themes.
Collector's Note "Maximize your screen content space by controlling the presence of Firefox window's Title bar (caption)" - Like Google Chrome Browser
TooManyTabs allows you to store as many tabs as you like by adding extra rows in the Firefox! It saves your browser's space and memory as idle tabs are put aside. The extra rows also help to better prioritize and visualize your tabs.
Add useful extra features to Gmail, like hierarchical labels, an unread message icon on your browser tab, file attachment icons, and more.
Select text and it's automatically copied to the clipboard. Also pastes on middle click.
After the Deadline is an intelligent grammar, style, and spell checker. It works with most web sites.
Press ctrl+shift+K (or) double-click to see its meaning. This extension is ideal for those who doesn't like to switch their window to see the meaning of a word. ...
Note from Mozilla: This add-on has been discontinued. Try PDF Viewer instead.
PDF plugin for Firefox 3 on Mac OS X. Displays PDF documents in the browser.