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.
Fight the text ads! Element Hiding Helper is a companion extension for Adblock Plus meant to make creating element hiding rules easier.
Adds toolbar buttons to the customize toolbar window in several programs including Firefox, Thunderbird and SeaMonkey. Some of the buttons make commonly preformed actions quicker, others add new functionality.
Fasterfox Lite: Performance and network tweaks for Firefox, without the Enhanced Prefetching. This is a fork from the original "Fasterfox".
Never lose anything you type into a web form again! Lazarus securely auto-saves all forms as you type, so after a crash, server timeout, or whatever, you can go back to the form, right click, "recover form", and breathe a sigh of relief.
Scrolls the page smoothly when scrolling the mouse wheel (or keyboard arrows if enabled).
Set Default FullZoom Level,
Toolbar buttons for Page zoom and Text zoom.
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.
Check4Change (aka C4C) is a simple extension that allows you to periodically check a web-page for updates...
3D in your browser! FoxTab brings innovative 3D functionality to your Firefox.
New! Top Sites for FoxTab (aka Speed Dial).
More Advanced (hidden) configures
Click a button or hit the hot-key to maximize (almost) any Flash content to the entire browser window. You can then enjoy your favorite games in any size you like, simply by resizing the browser window. Now with less bugs and more features...
Turns Idle FireFox into a ScreenSaver and Photo Viewer! Nice non-offensive pictures updated daily! Or your own pictures. FullScreen. Works great on Linux or dual monitors! Resouce Efficient! Support Media RSS. Recommend your own favorite pictures!