Collector's Note Great for code testing without having to edit or reupload the actual file.
Automate Firefox. Record and replay repetitious work. If you love the Firefox web browser, but are tired of repetitive tasks like visiting the same sites every days, filling out forms, and remembering passwords, then iMacros for Firefox is the soluti...
Restyle the web with Stylish, a user styles manager. Stylish lets you easily install themes and skins for Google, Facebook, YouTube, Orkut, and many, many other sites. You can even customize Firefox and other programs themselves.
The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of a browser.
The Web Developer extension adds various web developer tools to the browser.
FireShot Webpage Screenshots captures pages entirely. Demo: http://bit.ly/RlBQMV
The screenshot can be quickly captured and:
― Saved as Image or PDF
― Sent to clipboard
― Annotated *
― Uploaded *
― E-Mailed *
* OS Windows only
A customizable mouse gestures extension which enables to execute various commands and user scripts with six types of gestures.
Collector's Note This one isn't really as "necessary" as it is fun and useful for making things go a tad faster.
FirePath is a Firebug extension that adds a development tool to edit, inspect and generate XPath 1.0 expressions, CSS 3 selectors and JQuery selectors (Sizzle selector engine).
FEBE (Firefox Environment Backup Extension) allows you to quickly and easily backup your Firefox extensions. In fact, it goes beyond just backing up -- It will actually rebuild your extensions individually into installable .xpi files.
Easy and convenient screenshot tool. Allows you to make screenshots of any selected area (video and flash too), edit and upload it to server.