Blocks annoying video ads on YouTube, Facebook ads, banners and much more.
Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).
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.
Session Manager saves and restores the state of all or some windows - either when you want it or automatically at startup and after crashes. It can also automatically save the state of open windows individually.
AiOS lets you open various windows as sidebar panels, and quickly switch between them. So it put an end to the window chaos! In addition to bookmarks and history it opens dialogues such as downloads, add-ons and more in the sidebar.
Visual bookmarks for Firefox. (Works with all latest versions of Firefox)
Polish spell-check dictionary for Firefox 2.0/3.0pre, Thunderbird 2.0/3.0a1 and SeaMonkey 1.1/2.0a1...
Get international weather forecasts from AccuWeather.com and display them in any toolbar or statusbar with this highly customizable and unobtrusive extension.
British English Dictionary R1.19 for Firefox, Thunderbird and SeaMonkey by David Bartlett.
To enable, right-click in a multi-line text box, select "Languages", then "English / United Kingdom".
Add useful extra features to Gmail, like hierarchical labels, an unread message icon on your browser tab, file attachment icons, and more.
This add-on will open the File Browser at the right location, using simple filters on the downloaded file.
The filters are based on filenames and hosted domain's name.
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