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 Web Developer extension adds various web developer tools to the browser.
Get international weather forecasts from AccuWeather.com and display them in any toolbar or statusbar with this highly customizable and unobtrusive extension.
Use PDF Download to do whatever you like with PDF files on the Web. Regain control and eliminate browser problems, view PDFs directly in Firefox as HTML, and use the all-new Web-to-PDF toolbar to save and share Web pages as high-quality PDF files.
View HTTP headers of a page and while browsing.
Reloads web pages every so many seconds or minutes. The function is accessible via the context menu (menu you get when you right click on a web page) or via tab context menu (right click on the tab)
Draw a ruler across any webpage to check the width, height, or alignment of page elements in pixels.
A productive way to organize, read and share the content of your favorite feeds, blogs and news sites. Feedly offers a seamless transition from Google Reader.
Add useful extra features to Gmail, like hierarchical labels, an unread message icon on your browser tab, file attachment icons, and more.
TabGroups Manager helps to classify and organize tabs by dividing them into Groups. Because tabs become easier to manage, you can never have too many! TabGroups Manager is ideal for tab power users.
Creates a menu to access google bookmarks from any computer. Needs Google Account to use this extension.
Collections are groups of related add-ons that anyone can create and share.Explore Collections