Blocks annoying video ads on YouTube, Facebook ads, banners and much more.
Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).
The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of a browser.
Use tamperdata to view and modify HTTP/HTTPS headers and post parameters...
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!
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.
Professional Geo Add-on with security features and advanced network tools. Anti-phishing. Protection against DNS spoofing and fake sites. All DNS records for domain. The real location of web server, country flag, extended information about datacenter
Status bar widgets and progress indicators for Firefox 4+
Save an image of a web page (including Flash content) to a file. Web page screenshots may be captured interactively or from the command line. Options allow you to control the output format (PNG or JPEG), image file name, scaling, and much more.
Tired of going to History -> Recently Closed Tabs just to undo a closed tab? Then this extension is for you!
This extension allows you to undo closed tabs via a toolbar button or the right-click context menu.
A simple extension that counts the number of open tabs per window and displays the count in the toolbar...
Displays icon for user agent of received mails.
Collections are groups of related add-ons that anyone can create and share.Explore Collections