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).
Restyle the web with Stylish, a user styles manager. Stylish lets you easily install themes and skins for Google, Facebook, YouTube, Orkut, and many, many other sites. You can even customize Firefox and other programs themselves.
The Web Developer extension adds various web developer tools to the browser.
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!
IE Tab - an extension from Taiwan, features: Embedding Internet Explorer in tabs of Mozilla/Firefox...
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.
The original Gmail notifier for multiple accounts. Allows you to receive new mail notifications along with viewing account details including unread messages, saved drafts, spam messages, labels with new mail, space used, and new mail snippets.
We’re sorry to say we can’t maintain Skipscreen anymore. We’d love to see someone carry on with it. If you’d like to buy Skipscreen, or otherwise find it a good home, please contact us at firstname.lastname@example.org.
Monitors web pages for updates. Useful for websites that don't provide Atom or RSS feeds.
Brief makes reading RSS feeds as easy and intuitive as it gets. Designed to have exactly the right set of features, it is powerful and simple at the same time. Feeds are presented on a seamless, interactive page which let's you bookmark and tag items...
Automatically find user scripts on Userscripts.org (requires Greasemonkey or Scriptish)
This add-on will open the File Browser at the right location, using simple filters on the downloaded file.
The filters are based on filenames and hosted domain's name.