20 973 464 gebruikers
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).
1 425 983 gebruikers
The first and only download manager/accelerator built inside Firefox!
2 176 902 gebruikers
The best security you can get in a web browser!
Allow active content to run only from sites you trust, and protect yourself against XSS and Clickjacking attacks.
1 027 459 gebruikers
Download all the links, movies and audio clips of a page at the maximum speed with a single click, using the most popular, lightweight and reliable external download managers.
1 072 144 gebruikers
Organize your schedule and life's important events in a calendar that's fully integrated with your Thunderbird email. Manage multiple calendars, create your daily to do list, invite friends to events, and subscribe to public calendars.
146 878 gebruikers
OpenPGP message encryption and authentication for Thunderbird and SeaMonkey.
104 287 gebruikers
ReminderFox displays and manages lists of reminders and ToDo's. ReminderFox makes sure you remember all of your important dates via easy-to-use lists, alerts, and alarms, right in your browser without the need for a separate calendar program.
124 969 gebruikers
StumbleUpon is the easiest way to discover new and interesting photos, videos, web pages and more, recommended by a community of experts. Tell us what you are interested in and we recommend page after page of amazing stuff you’d never expect to see.
17 336 gebruikers
NewsFox is an efficient 3-pane(email) style Atom/RSS feed reader.
17 452 gebruikers
Add useful extra features to Gmail, like hierarchical labels, an unread message icon on your browser tab, file attachment icons, and more.
1 513 gebruikers
Firefox based theme for SeaMonkey 2.x
4 351 gebruikers
ScribeFire Classic is a blog editor that integrates with Firefox and lets you easily post to your blog.
ScribeFire Classic is no longer supported; you should install ScribeFire Next: https://addons.mozilla.org/en-US/firefox/addon/scribefire-next