- Duplicate Contact Manager - Shows side-by-side duplicates and allows one to save whichever of them one likes, with an opportunity to edit information first, including copying and pasted from the soon-to-be-deleted item to the item-to-be-saved. Sure, you could do it yourself, but this is easier. Kind of slow search, though, so do other things and come back to it, as it works, and you'll be fine.
- EagleEye (beta as of this writing) -- A neat way to keep an eye on your contact list. Allows you to set filters to keep track of folks you have not contacted in a while, or ever, along with enormous other filtering opportunities. Check it out and have fun with it.
- Enigmail - Free OpenPGP encryption for your Thunderbird.
- Lightning - A Calendar in your Thunderbird
- Provider for Google Calendar -- Integrate your Google Calendar with your Thunderbird Lightning calendar (see above).
- Quote Colors - Add colored quote text to your emails. This adds functionality similar to Outlook's own.
- Zindus - Synch contacts with Google and Zimbra.
Have some of your own? Post a comment to this blog entry.