User Agent Changer Requires Restart
Adds a menu and a toolbar button to change the user agent of a browser.
Page Hacker Revived Requires Restart
Adds a toolbar to edit and format the current page
Fire IE (FireIE, Enhanced IE) Requires Restart
Embeds Internet Explorer(IE) to use the powerful Firefox add-ons.
Not only an enhanced IE Tab, but also an enhanced Internet Explorer with Adblock Plus and FireGestures support.
Switch to the IE engine in one click and dismiss your IE.
Functionality for multiple screens and windows. Easily open links in other windows or on other screens, move or merge tabs, and move or merge entire windows. With graphical controls for grid positioning.
Generic CSS Loader 2 Requires Restart
A very basic CSS loader for Firefox. No fancy features, just an alternative to userChrome and userContent files.
Sync engine for RequestPolicy.
Sync engine for Stylish with backup / restore facility.
Display the graph created by cycle collector. Open "about:ccdump" page after the installation.
Transform the colors of entire web pages or selected elements. Combine predefined themes with basic transforms. Save transforms for specific web domains.
Send to xNode Requires Restart
Sends content to xNode for analysis. Provides information on domain names, IP addresses, eMail addresses, certificates and much more.
Copy Pure Text Requires Restart
Allows to copy selected text as plain text by adding a 'Copy as Text' menu item to context menu.
In the DOM Inspector,quickly navigate to the any elements
Integrate MXR with vim
foxmeter Requires Restart
An HTTP analyzer addon for Firefox, fork from HttpFox with features like: summary by host, and more coming soon
eCleaner Requires Restart
Clears preferences left by extensions after uninstallation
Fetch Text URL (fix version) Requires Restart
Open text URLs from the context menu.
bbeContainer Requires Restart
an extension that allows users to edit local files with browser-based editors.
UPDATE: XPI delay has been removed in Firefox 40!
Disable the install delay in Firefox. New 2.0 version now includes GreaseMonkey scripts!
Unlike similar addons, this works on Firefox 4 and beyond.
This 15KB restartless add-on will add a "File" -> "Restart" menu item and a ctrl/cmd + alt + r hotkey to restart Firefox or Seamonkey.