ImportExportTools Requires Restart
Adds some tools to import and export folders and messages
ChatZilla Requires Restart
A clean, easy to use and highly extensible Internet Relay Chat (IRC) client.
Mail Redirect Requires Restart
Allow to redirect (a.k.a. "remail") mail messages to other recipients.
Join-NG Requires Restart
Join partial messages. Somewhat similar to MS Outlook Express "combine and decode".
Quote Colors Requires Restart
Quote Colors allows you to select text and background colors of different quote levels which are applied when reading or printing mail/news messages. Additionally, you can choose between graphical and traditional plain text quoting display mode.
Lightbird Requires Restart
Standalone calendar UI for Lightning
Flexible Identity Requires Restart
Selects an identity based on the recipients list when sending an email
Session Manager saves and restores the state of all or some windows - either when you want it or automatically at startup and after crashes. It can also automatically save the state of open windows individually.
Gmail Manager NG Requires Restart
Based on Gmail Manager by Todd Long. This fork is intended to a supported version of Gmail Manager since Todd appears to have gone MIA. Manage multiple Gmail accounts and receive new mail notifications.
Use SeaMonkey as a standalone e-mail client. Set up a default browser for links opened from Mail & Newsgroups.
Year view Requires Restart
Year view for calendar.
QuickNote Requires Restart
A simple note-taking extension.
Send Filter Requires Restart
This add-on allows you run your message filters automatically on outgoing messages after sending. In other words, it's a outgoing filter for thunderbird and seamonkey.
Contact Photos Requires Restart
Displays contact photos in the message header.
PlayFlash 32bit Requires Restart
Flash player plugin - unofficial xpi repack for 32bit browsers.
Use when official plugin installer is not suitable.
All binary files are copyrighted by their authors and distributed for free.
Clean Subject Requires Restart
"Clean Subject" cleans the subject from multiple occurrences of subject prefixes such as ("Re: Re-2: Re:") and postfixes that are inserted by other clients. Words like "[SPAM]" can be cleaned as well. These prefixes can be defined in the preferences.
Copy Plain Text 2 Requires Restart
Copies text without formatting
Diagnostics tool for Adblock Plus, provides some insight into internal processes of Adblock Plus.
PlayFlash 64bit Requires Restart
Flash player plugin - unofficial xpi repack for 64bit browsers. Use when official plugin installer is not suitable. All binary files are copyrighted by their authors and distributed for free.
Reinstates the extensions.checkCompatibility preference.