Send Later Requires Restart Featured
True "Send Later" functionality to schedule the time for sending an email.
Signature Switch Requires Restart Featured
Switch the signature on/off or choose a new one from your predefined set.
Mail Merge Requires Restart
Create and Save or Send Multiple Individual and Personalized Messages from a Draft
Allows you to use your Exchange email accounts that use Outlook Web Access (OWA) with Thunderbird
Check and Send Requires Restart
Check the message contents and addresses before you send the message...
Flex Confirm Mail Requires Restart
Confirm mail address and attachments based on flexible rules.
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!
Emoji Requires Restart
Add emojis to your e-mails.
ThunderPEC Requires Restart
ThunderPEC semplifica la gestione della Posta Elettronica Certificata (PEC) e delle comunicazioni PCT e FatturaPA in Thunderbird.
Send Later Button Requires Restart Featured
A simple button to invoke the (already existing) send later functions.
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.
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.
Grammar Checker Requires Restart Featured
Checks grammar using LanguageTool.
Shrunked Image Resizer Requires Restart
Make your photos smaller, so they don't take forever to email.
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).
Uploads your large attachments to your Dropbox instead of sending them by email. This uses Thunderbird's FileLink feature.
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.
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).
Highlighter Requires Restart
Quickly highlight some text in Thunderbird message composing windows.
ReplyWithHeader Requires Restart
Outlook style headers and few goodies for Thunderbird & Postbox.