Use the Evernote Web Clipper to save things you see on the web into your Evernote account.
Allows bidirectional access to Google Calendar
Access to Google contacts and synchronize them with Thunderbird address books.
This addon provides a conversation view for Thunderbird, grouping messages together and allowing you to reply "inline" thus providing a more efficient workflow.
The latest version is compatible with Thunderbird 31+ only (see below for details).
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.
Allows several tweaks to the Thunderbird/Lightning calendar user interface including new selection styles and repeating event icons. Mimics the colors and styles found in MS Outlook.
Toolbar-Buttons for Lightning; advances the feature to get rid of the tabbar.
Note from Mozilla: This add-on has been discontinued. Try MinimizeToTray Revived instead.
Minimize applications to the system tray.
All-in-one Mac style theme! Please check preview here first (it rocks):
To get sub themes: Open Add-ons window, right click on Cutebird, click "About Cutebird"
more info at http://foxdie.us