Use the Evernote Web Clipper to save things you see on the web into your Evernote account.
Quicktext is an extension for Thunderbird that lets you create templates that can be easily inserted into your own emails.
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 for customization of the folder pane. Accounts can be rearranged and the startup folder can be chosen.
Displays icon for user agent of received mails.
Removes comment, display name automatically from addresses before sending mail.
Minimizes Mozilla windows into the system tray. Also includes a right clickable tray icon menu to further load only the windows you want visible...
Collapse and expand quotes. Please see the extension homepage for...
Quote Colors allows you to select text and background colors of different quote levels which are applied when reading or printing mail/news messages. Additionally, you can choose between graphical and traditional plain text quoting display mode.
Keyboard shortcuts to change folder, move/copy messages, with folder name auto-completion.
Auto Zip Attachments allows you to easily compress (zip) attachments.