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).
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.
17,280 weekly downloads
DuckDuckGo is a search engine that does not track you. Adds DuckDuckGo (HTTPS / SSL version) to the search bar. For more features, see the DuckDuckGo Plus add-on.
14,849 weekly downloads
This add-on will add an improved version of YouTube's search engine, now with search suggestions!
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OpenPGP message encryption and authentication for Thunderbird and SeaMonkey.
A clean, easy to use and highly extensible Internet Relay Chat (IRC) client.
TinEye is a reverse image search engine. The plugin adds a context menu item that allows you to search for an image to find out where it came from, how it is being used, if modified versions of the image exist, or to find higher resolution versions.
Allows you to quickly switch to a different language (User Interface, Spell Checker Dictionary and Website content) in your Mozilla application.
Manage form history entries (search, edit, cleanup, export/import) and easy text formfiller.
Auto-save text entered in any form while typing to allow fast recovery when disaster strikes.
Control for which webpage form history is saved or not.
Displays the address books in a sidebar in Thunderbirds 3-pane-window and can be toggled with the F4 key or a toolbar button.
Visit my Contacts Sidebar site for recent versions and news.
Sets permanent opt-out cookies to stop behavioral advertising for 100+ different advertising networks, including Google, Yahoo, Microsoft, all members of the Network Advertising Initiative, and many other companies.
Display birthdays from the Thunderbird addressbooks as events in Lightning.
Facilitates handling of duplicates in your address book(s). Allow to search and remove similar contacts.
Collections are groups of related add-ons that anyone can create and share.Explore Collections