Stop Ignoring Reply:To Requires Restart
Default "Reply" functionality pays attention to "Reply-To" in original email
ThunderHTMLedit Requires Restart Featured
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.
Send Later Requires Restart Featured
True "Send Later" functionality to schedule the time for sending an email.
MEGAbird Requires Restart
Add MEGA support to Thunderbird's Filelink feature.
ThunderPEC Requires Restart
ThunderPEC semplifica la gestione della Posta Elettronica Certificata (PEC) e delle comunicazioni PCT e FatturaPA in Thunderbird.
CategoryManager 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).
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.
Mail Merge Requires Restart
Create and Save or Send Multiple Individual and Personalized Messages from a Draft
Address bulk copy （アドレス一括コピー） Requires Restart
Thunderbird は Outlook のようにアドレス全選択からの「一括コピー」ができません。
Custom Address Sidebar Requires Restart
Allow you to help address sidebar more useful.
Automatic Dictionary Requires Restart
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.
Markdown Here Requires Restart
Write your email in Markdown, then make it pretty.
Warns if you send mail from or to a specified domain. If there are multiple accounts in your profile, you can isolate one so that you can't send mail to that domain from outside or vis versa without warning.
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.
SmartTemplate4 Requires Restart
SmartTemplate⁴ offers an easy and powerful way to automatically create customized replies by auto-inserting various mail headers. Templates can be created for every mail identity, Stationery files can now be imported and used directly.
ReplyWithHeader Requires Restart
Outlook style headers and few goodies for Thunderbird & Postbox.
Color Text Compose Buttons Requires Restart
Adds Text Color Buttons in Compose Toolbar and More: Pixel FontSize, Strikethough, Sub & Superscript, Lower & UpperCase. Also provide Tools: Insert iframe, Launch MathType, Maths & Greek Symbols, Load Template Variables and Duplicate Compose Window.
Extra Format Buttons Requires Restart
Adds a font size (in pixels), strikethough, subscript and superscript buttons to Thunderbird's Compose Window.
SmilieInserter Plus Requires Restart
Insert smilies in messages.
DL for Thunderbird Requires Restart
Allows to convert large attachments to links automatically without 3rd party providers.