Manage your daily schedule directly within Thunderbird. Allows managing calendars locally or subscribing to network calendars.
Minimize applications to the system tray. Works for Firefox 3, Thunderbird 3 and Sunbird 1 and higher. Highly configurable with a number of user changeable options.
Foxclock is an extension that lets you keep world time by putting small clocks in your status bar. Next time when you send an email to your partner, you will know why he doesn’t reply to you instantly. He could most probably be sleeping in his country.
Folder Tabs – Cut through the clutter of the folders sidebar with your most important folders as tabs. Open folders and sub folders, move mails without scrolling around or searching. Use categories for filtering.
ReminderFox is an extension for Thunderbird that displays and manages events 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.