When you find something on the web that you want to view later, put it in Pocket. It automatically syncs to your phone, tablet or computer so you can view it at any time, even without an internet connection.
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.
A Statusbar with speed, percentage, time and loaded size (similar to Opera's one)
Screengrab! saves webpages as images... but not for new versions of Firefox.
FF changes too fast and I don't have the time to maintain it anymore. Bugs have developed that I am not in a position to investigate.
Therefore, Screengrab is EOL.
Autosizes the searchbar as you type, cleans the query or reverts to your default search engine after submitting. Supports almost all themes and various search bar related extensions. Useful for saving space on a small screen.
Fission combines address bar and progress bar (Safari style). This makes the progress bar more visible and allows for a nice visual effect.
Tabs Open Relative makes all new tabs open to the right of the current tab, rather than at the far right of the tab bar (optionally this only applies to links).
Collections are groups of related add-ons that anyone can create and share.Explore Collections