Clippings Requires Restart
Save frequently-entered text for pasting later.
Auto Resize Image Requires Restart
Resizer for inline and attachment images (JPEG, PNG, BMP and GIF image formats).
All platforms are supported (Windows, Linux and Macintosh).
Mail Merge Requires Restart Featured
Mass Mail and Personal Mail
Send Later Requires Restart
True "Send Later" functionality to schedule the time for sending an email.
Signature Switch Requires Restart
Switch the signature on/off or choose a new one from your predefined set...
MEGAbird Requires Restart
Add MEGA support to Thunderbird's Filelink feature.
Emoji Requires Restart
Add emojis to your e-mails.
Check and Send Requires Restart
Check the message contents and addresses before you send the message...
Stationery Requires Restart
Extension to mimic Outlook Express Stationery.
Allow you to use HTML files as templates for mail. Also allow custom template in replies or forwarded mail!
ThunderPEC Requires Restart
ThunderPEC semplifica la gestione della Posta Elettronica Certificata (PEC) e delle comunicazioni PCT e FatturaPA in Thunderbird.
SmartTemplate4 Requires Restart
SmartTemplate4 offers an easy way to automatically create customized replies by auto-inserting various mail headers. Templates can be created for every account as well as for the default (all email accounts). Also supports the Stationery Add-on.
AVIM Requires Restart
Vietnamese-language input method editor (IME). Type diacritics directly into any Web page, Web app, or dialog box. Convenient, comprehensive, secure.
Bộ gõ tiếng Việt cho phép đặt dấu trực tiếp vào bất kỳ trang Web, ứng dụng Web, hộp thoại.
Emoji Menu Requires Restart
Adds the ability to easily insert emojis into your composed messages in Thunderbird.
Markdown Here Requires Restart
Write your email in Markdown, then make it pretty. NOTE: This is the legacy XUL version, for Thunderbird, Postbox, Pale Moon, etc. *Not* for modern Firefox; for that use this: https://addons.mozilla.org/en-US/firefox/addon/markdown-here/
As-you-type phonetic conversion of text from one alphabet to another, as well as transliteration/detransliteration of selected text anywhere within documents. Supports multiple languages and custom transliteration schemes.
Remembers the language you use with a person or group of people, and switches the spellchecker language automatically for you next time. You do not have to do it manually any more. It remembers and switches it for you.
Nextcloud for Filelink Requires Restart
"Nextcloud for Filelink" is an Open Source Thunderbird extension which makes it easy to send large attachments with Thunderbird by uploading them first to a Nextcloud server and by then inserting the link into the body of your email.
ThunderHTMLedit Requires Restart
Thunderbird HTML editor. This add-on adds a HTML tab to the composition window where you can see and edit the HTML source of the message.
CategoryManager 2 Requires Restart
Category manager for Thunderbird contacts, also allows to send an email to all members of a category (categories can be used as contact groups).
Highlighter Requires Restart
Quickly highlight some text in Thunderbird message composing windows.