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QuickFolders (Tabbed Folders)

The "Swiss army knife" of folders. Turn your favorites into tabs - open folders and subfolders, move mails without scrolling around or searching. powerful + easy.

See new mail at a glance after automatic filtering - supports quickFilters addon!

Rated 5 out of 5 stars (187)
14,866 users

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Ukrainian dictionary

Ukrainian (uk-UA) spellchecking dictionary

Rated 5 out of 5 stars (57)
11,472 users

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General Catalan dictionary

Free Catalan (general version) spelling dictionary.

Rated 4 out of 5 stars (40)
12,523 users

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Canadian English Dictionary

For some reason, Mozilla doesn't have a Canadian localization team, but I know that even the British dictionary doesn't quite cut it for the truly patriotic.

Rated 4 out of 5 stars (82)
9,454 users

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Emoji

Add emojis to your e-mails.

Rated 4 out of 5 stars (64)
24,328 users

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Addressbooks Synchronizer

Synchronizes selected addressbooks with other instances of thunderbird
using local files, webdav servers or imap servers

Rated 4 out of 5 stars (79)
24,583 users

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German Dictionary, classical spelling standards

German Dictionary according to the classical spelling standards for spell-checking in Firefox and Thunderbird

Rated 5 out of 5 stars (20)
9,390 users

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quickFilters

Quickly generate mail filters on the fly, by dragging and dropping mails and analyzing their attributes. Create a filter in less than 10 seconds, it's as easy as: drag, click, click.

By popular demand, supports SORTING filters alphabetically.

Rated 5 out of 5 stars (70)
14,321 users

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Check and Send

Check the message contents and addresses before you send the message...

Rated 4 out of 5 stars (49)
20,756 users

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Signal Spam

Add simple functions to report spams or phishing to Signal Spam by one click.
The add-on will also alert you if you open a fraudulent e-mail (phishing).

Rated 3 out of 5 stars (163)
16,437 users

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SmartTemplates Featured

SmartTemplates 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.

Rated 5 out of 5 stars (79)
5,104 users

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Confirm-Address

Confirm E-mail address before sending mail

Rated 4 out of 5 stars (73)
21,215 users

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Hungarian Dictionary

This extension is based on László Németh's Hungarian Dictionary

Rated 4 out of 5 stars (56)
8,887 users

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Český slovník pro kontrolu pravopisu

Slovník pro kontrolu pravopisu pro aplikace Mozilla

Rated 4 out of 5 stars (36)
14,935 users

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German Dictionary, extended for Austria

German dictionary (new Orthography) for spellchecking in Mozilla products, extended with Austrian words

Rated 5 out of 5 stars (22)
5,269 users

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XNote++ Featured

Persistent sticky notes associated to emails. You can fulltext search with constraints/email them/print/bookmark/copy to clipboard.

If you have a large screen, you can even display the notes outside of TB's main window, so it won't hide anything.

Rated 4 out of 5 stars (128)
20,553 users

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German Dictionary (Switzerland)

Dictionary with Swiss variants of German words for spellchecking in Mozilla products

Rated 5 out of 5 stars (3)
14,069 users

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Automatic Dictionary

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.

Rated 5 out of 5 stars (49)
3,648 users

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Tag Toolbar / Tag Popup

Add toolbar for toggling tags.

Rated 4 out of 5 stars (84)
16,307 users

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AutoarchiveReloaded Featured

Automatically archives old mails (Improved version of the orginal Autoarchive Add-on)

Rated 4 out of 5 stars (25)
22,622 users

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