Thunderbird add-ons that I've either used for years, or tested and highly suggest.
Reinstates the extensions.checkCompatibility preference without respect to the current application version.
Quicktext is an extension for Thunderbird that lets you create templates that can be easily inserted into your own emails.
Add symbol in header plane to switch between compact and expanded view. Options to switch between one or two lines compact view, which buttons should be displayed in header pane. Linkify RSS subject. Optionally darkens header if message has focus.
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.
Extracts all attachments from selected messages and then can delete, detach or mark-read.
Synchronizes selected addressbooks with other instances of thunderbird
using ftp/webdav/imap servers
Allows for customization of the folder pane. Accounts can be rearranged and the startup folder can be chosen.
Menambahkan lebih banyak menuitem pada menu konteks di Pengelola Pengaya.
The "Swiss army knife" of folders. Turn your favorites into tabs - open folders and subfolders, move mails without scrolling around or searching. powerful + easy.
See new mail at a glance after automatic filtering - supports quickFilters addon!
Thunderbird Message Filter Import/Export is a thunderbird/mozilla extension to import/export message filters.
Displays icon for user agent of received mails.
Check the message contents and addresses before you send the message...
abandoned, use Stylish Custom Add-on instead
custom additions to Stylish extension.
brings back features from 0.5.9 and adds new features