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!
Are you concerned about your privacy? Or, are you blocked from some websites by a firewall? And, are you arming yourself with a proxy? In that case, AutoProxy is designed for you! A tool to help you use your proxy automatically & efficiently.
HTML Validator is a Mozilla extension that adds HTML validation inside Firefox and Mozilla. The number of errors of a HTML page is seen on the form of an icon
For Firefox 23+, you need 0.958 (under review)
Help make Firefox better. The Add-on Compatibility Reporter enables you to report if the Firefox add-ons that you're using are working properly.
GMarks helps you sync & manage your bookmarks with Google Bookmarks...
SenSEO is an extension checking the most important on-page-SEO-criteria and calculating a grade of how good your site fulfills these criteria.
Collections are groups of related add-ons that anyone can create and share.Explore Collections