FEBE (Firefox Environment Backup Extension) allows you to quickly and easily backup your Firefox extensions. In fact, it goes beyond just backing up -- It will actually rebuild your extensions individually into installable .xpi files.
Autofill Forms enables you to fill out web forms with one click.
— Open web pages saved with Internet Explorer or other browsers (MHT)
— Save many tabs, video and audio reliably, in a single ZIP file (MAFF)
— Return to the original site you saved a page from, and more!
Attempting to reduce both Browser and Flash RAM Memory usage. Memory Fox will promote the increase of available RAM memories for other application processes. Hopefully, fostering any attempts of Memory Recovery and Retention.
Better YouTube experience. Provides 'Smart Buffer' for slow connections; auto loop; buffer preferences; quality selection; and more.
Allows Firefox to reload multiple images that failed to be displayed.
UnMHT allows you to view MHT (MHTML) web archive format files, and save complete web pages, including text and graphics, into a single MHT file in Firefox/SeaMonkey.
Status bar widgets and progress indicators for Firefox 4+
Full featured zoom manager with independent page and image zoom modes. Choose from four zoom modes: Default Zoom, Fit-To-Width, Default Zoom + Site Specific or Fit-To-Width + Site Specific. Button style and zoom levels are fully configurable.
TinEye is a reverse image search engine. The plugin adds a context menu item that allows you to search for an image to find out where it came from, how it is being used, if modified versions of the image exist, or to find higher resolution versions.