The first and only download manager/accelerator built inside Firefox!
Tab Mix Plus enhances Firefox's tab browsing capabilities. It includes such features as duplicating tabs, controlling tab focus, tab clicking options, undo closed tabs and windows, plus much more. It also includes a full-featured session manager.
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!
Advanced Eyedropper, Color Picker, Gradient Generator and other colorful goodies...
IE Tab - an extension from Taiwan, features: Embedding Internet Explorer in tabs of Mozilla/Firefox...
A clean, easy to use and highly extensible Internet Relay Chat (IRC) client.
Add useful extra features to Gmail, like hierarchical labels, an unread message icon on your browser tab, file attachment icons, and more.
Signatures for Gmail, Google Mail, Yahoo Mail
Screengrab! saves webpages as images... but not for new versions of Firefox.
FF changes too fast and I don't have the time to maintain it anymore. Bugs have developed that I am not in a position to investigate.
Therefore, Screengrab is EOL.