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.
German Dictionary (new Orthography) for spellchecking in Mozilla products
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".
Quicktext is an extension for Thunderbird that lets you create templates that can be easily inserted into your own emails.
Allow to redirect (a.k.a. "bounce") mail messages to other recipients
MagicSLR extends functions and buttons to get and send messages. Many users missed a combined "Get/Send" button in Thunderbird. MagicSLR provides this button and more.
Ever sent mail from the wrong email address because you forgot to select the correct identity in the compose window?
Collections are groups of related add-ons that anyone can create and share.Explore Collections