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Flexible Identity Requires Restart

Selects an identity based on the recipients list when sending an email

Rated 4 out of 5 stars (39)
227 users

SeaTab-X-2 Requires Restart

Adds Firefox-style tab closers into SeaMonkey.

Rated 5 out of 5 stars (22)
213 users

ThunderBirthDay Requires Restart

Display birthdays from the Thunderbird addressbooks as events in Lightning.

Rated 4 out of 5 stars (97)
211 users

Disable Add-on Compatibility Checks

Reinstates the extensions.checkCompatibility preference without respect to the current application version.

Rated 4 out of 5 stars (120)
205 users

Saved Password Editor Requires Restart

Adds the ability to create and edit entries in the password manager.

Rated 5 out of 5 stars (390)
201 users

Folderpane Tools Requires Restart

Allows for customization of the folder pane. Accounts can be rearranged and the startup folder can be chosen.

Rated 3 out of 5 stars (125)
199 users

Theme Font & Size Changer for ThunderBird

Theme Font & Size Changer lets you change the global font size and font family used for the user interface in Firefox. Design your browser with your favorite font.

Rated 3 out of 5 stars (100)
176 users

SeaMonkey Debug and QA UI Requires Restart

Provides Additional Debug and QA UI for SeaMonkey development and testing.

Rated 3 out of 5 stars (3)
173 users

Image Zoom Requires Restart

Adds zoom and rotation functionality for images...

Rated 4 out of 5 stars (355)
170 users

User Agent Switcher Requires Restart

The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of a browser.

Rated 4 out of 5 stars (336)
161 users

Session Manager

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.

Rated 5 out of 5 stars (850)
152 users

Easiest YouTube Video Downloader

This Addon simply adds a dropdown button that lets you download YouTube Videos in various Formats. Download YouTube Videos in FLV, 3GP, MP3, MP4, 720p, 1080p in a single click.

Rated 3 out of 5 stars (47)
149 users

Return Receipt Toolbar Button Requires Restart

Allow you to add a Return Receipt button to mail compose window toolbar.

Rated 5 out of 5 stars (21)
128 users

Lightbird Requires Restart

Standalone calendar UI for Lightning

Rated 4 out of 5 stars (21)
128 users

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.

Rated 5 out of 5 stars (52)
124 users

Cookies Exterminator

Auto delete cookies, localStorage and IndexedDB objects as soon as they become unused

Rated 5 out of 5 stars (17)
122 users

Extra Format Buttons Requires Restart

Adds a font size (in pixels), strikethough, subscript and superscript buttons to Thunderbird's Compose Window.

Rated 4 out of 5 stars (19)
122 users

Bluhell Firewall

Get a faster browsing experience by blocking nasty web resources using Bluhell Firewall, the lightweight Ad-Blocker and Tracking/Privacy Protector.

Rated 4 out of 5 stars (498)
118 users

AMO Browsing for SeaMonkey

This extension makes browsing for extensions easier at addons.mozilla.org. It fixes incorrect information about some extensions being not available for SeaMonkey and adds links to the Add-on Converter where needed.

Rated 5 out of 5 stars (6)
111 users

FireFTP Requires Restart

FireFTP is a free, secure, cross-platform FTP/SFTP client for Waterfox which provides easy and intuitive access to FTP/SFTP servers.

Check out my new project, FireSSH!

Rated 4 out of 5 stars (1,070)
111 users