Mailopen Requires Restart
Open an email file from the commandline
Lowercase Email Addresses in Message Headers Requires Restart
Shows lowercase email addresses in message headers and their tooltips.
Large Fonts Requires Restart
This add-on enables you to change the font size of the plain text editor of Thunderbird.
Dialectic Dialer Requires Restart
Dial phone numbers with Dialectic (Dialectic is for OS X only). In addition, when a page loads, phone numbers can optionally be highlighted and hyperlinked to dial Dialectic.
ToggleFullHeaders Requires Restart
Allows you to customise the message panel buttons to add a "Toggle Headers" button that will switch between showing and hiding the full headers.
Mukparasi Requires Restart
A Korean popup dictionary based on Rikaichan
Requires the additional dictionary addon.
Disable about:config Requires Restart
Disable about:config feature of Firefox and Thunderbird.
Lightning Invitation Notifier Requires Restart
This extension is an extension to Mozilla Lightning for Thunderbird.
It shows a toast message and opens the invitations window when an invitation arrives.
Generate e-bay templates online - in few minutes.
Delete Read Emails Requires Restart
Adds a button in Thunderbird's toolbar that enables you to delete all your read emails at once
Edit Message Encoding Fallback Requires Restart
Fallback to a safe encoding, if you are replying to a message with unsupported encoding like UTF-16LE. (workaround for the Bug 961983)
JIRA Integration Plugin (Beta) Requires Restart
Create Jira Tickets directly from within Mozilla Thunderbird (based on E-Mails). This Addons saves your Username and Password in clear text. Use on your own risk. (Also, you might need to disable the CSRF Filter in your JIRA Instance.)
Zoiper Thunderbird Plugin Requires Restart
It allows you to make calls via Zoiper Communicator from Mozilla Thunderbird.
Attach from Clipboard Requires Restart
Create file attachments directly from the system clipboard.
Reply To All Reminder Requires Restart
Asks for confirmation when "Reply" instead of "Reply to All" is pressed on an email with multiple recipients.
SMTP Switch Reborn Requires Restart
Earn extra money while browsing online! Get rid of ads, and optionally tip your favorite sites.
Thunderbook Requires Restart
Export messages (including RSS items) as e-books.
AastraClickToCall Requires Restart
Converts telephone numbers into clickable links for use with Aastra IP Phones
MultiTemplateLoader Requires Restart
Manages & applies multiple HTML templates when creating/replying messages.
Templates may be either local files or online links (http:// or ftp://). Up to 9 templates can be defined and easily switched, also using shortcut keys.