Most Popular Extensions
Dorando keyconfig Requires Restart
A modified Dorando's addon to rebind keyboard shortcuts. It is designed to be a drop-in replacement, keeping your old settings. (See details for upgrade instructions.)
Get a faster browsing experience by blocking nasty web resources using Bluhell Firewall, the lightweight Ad-Blocker and Tracking/Privacy Protector.
Minimum and fast URL blocker.
"Restart" menu and button, with configurable shortcut key.
No need flash plugin on embeded youtube movies
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.
Block advertisement and access to adult sites
Deny resource:// access to Web content: We fill the hole to defend against fingerprinting. Very important to Firefox privacy. A direct workaround for bugzil.la/863246
Search with Joy! Block Ads While Surfing!
All the great features of /u/RemindMeBot in a quick and easy to use extension!
Crash yourself with ease
Important note: This extension will not work in Firefox 57 and above. Providing this functionality in Firefox is no longer possible, the extension is discontinued.
Cleans your Firefox, Thunderbird, SeaMonkey, Fennec (unstable), Instantbird and BlueGriffon.
Manages the Remote XUL whitelist to allow websites and local files to load XUL content. For versions compatible with Firefox 41 and lower, see All Versions page below.
Avoid redirects and has direct access to the sites you want to visit.
Adds an about:addons-memory page that details add-on memory usage
Generate e-bay templates online - in few minutes.
lolifox - Fierr MOD Requires Restart
Replaces the error page with a lolifox appearance with additional features.
With MyAdFilter, free content creators propose you only one ad. Apart from those, as your usual ad-blocker, MyAdFilter disables all ads.
URL Fixer fixes common typos in URLs entered in the address bar. It will fix errors like "google.con" or "youtube,com". You have the option of being asked to confirm corrections before they are applied.