Addons for Thunderbird, useful not only for visually impaired users.
OpenPGP message encryption and authentication for Thunderbird and SeaMonkey.
Did your friend send you a cool link? Want to read the rest of that interesting article? Don't want to open up your web browser just to view it? You don't have to! Just view it in Thunderbird with ThunderBrowse!
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.
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.