Use the Evernote Web Clipper to save things you see on the web into your Evernote account.
Evernote Clearly makes blog posts, articles and webpages clean and easy to read. Save them to Evernote to read anywhere.
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.
Pick images while you browse.
Choose (filter) images and save images from web page to local disk.
Be in control of which cross-site requests are allowed. Improve the privacy of your browsing by not letting other sites know your browsing habits. Secure yourself from Cross-Site Request Forgery (CSRF) and other attacks.
Adds an about:addons-memory page that details add-on memory usage
Allows URI texts written in webpages to be loaded by double clicks.
DOM Inspector is a tool that can be used to inspect and edit the live DOM of any web document or XUL application. The DOM can be navigated using a two-paned window displaying a variety of different views on the document and all nodes within.
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.
Translate status updates and comments on Facebook. Seamlessly integrates into Facebook.
Get international weather forecasts from AccuWeather.com and display them in any toolbar or statusbar with this highly customizable and unobtrusive extension.
GMarks helps you sync & manage your bookmarks with Google Bookmarks...
Show the likes and dislikes bar over every video thumbnail in YouTube so that you can know its rating before watching it.