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.
NOTE: Xmarks lives! Learn more at http://blog.xmarks.com . Xmarks is the #1 bookmarking add-on. Keep your bookmarks, passwords and open tabs backed up and synchronized across computers and browsers.
A customizable mouse gestures extension which enables to execute various commands and user scripts with six types of gestures.
Make any pages' search functionality available in the Search Bar (or "search box")...
Expands the context menu's 'Search for' item into a list of installed search engines, allowing you to choose the engine you want to use for each search.