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Provider for Google Calendar

Allows bidirectional access to Google Calendar

Rated 3 out of 5 stars (1,653)
168,915 users

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British English Dictionary (Marco Pinto)

A fork of Mark Tyndall's add-on, based on David Bartlett's
British Dictionary R1.19 for Firefox, Thunderbird and SeaMonkey.

V3.3.5 has 140 000+ new words and also fixes.

Rated 5 out of 5 stars (83)
152,362 users

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English United States Dictionary

English United States (en-US) Dictionary as shipped with Thunderbird 115 ESR and Firefox 115 ESR.

Rated 4 out of 5 stars (39)
62,100 users

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German Dictionary

German Dictionary (new Orthography) for spellchecking in Mozilla products

Rated 4 out of 5 stars (82)
228,343 users

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Spanish (Spain) Dictionary

Spanish/Spain Dictionary

Rated 4 out of 5 stars (167)
46,068 users

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CardBook Featured

A new Thunderbird address book based on the CardDAV and vCard standards.

Twitter: @CardBookAddon

Rated 4 out of 5 stars (447)
62,172 users

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ExQuilla for Exchange

Thunderbird email accounts connecting to Microsoft Exchange Web Services.

Rated 4 out of 5 stars (134)
4,428 users

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Mail Merge

Create and Save or Send Multiple Individual and Personalized Messages from a Draft

Rated 5 out of 5 stars (227)
58,620 users

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LookOut (fix version)

LookOut decodes winmail.dat (TNEF encoded) files that may come from a misconfigured Microsoft Exchange server or Outlook user allowing access to the original attachments
Support: Thunderbird

Rated 4 out of 5 stars (96)
148,218 users

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DKIM Verifier Featured

Verifies the DKIM-Signature of an e-mail.

Rated 4 out of 5 stars (47)
17,962 users

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Dizionario italiano

Add support for Italian to spellchecking

Rated 4 out of 5 stars (71)
48,603 users

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Send Later

True "Send Later" functionality to schedule the time for sending an email.

Rated 5 out of 5 stars (263)
87,795 users

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Quicktext

Quicktext is an extension for Thunderbird that lets you create templates that can be easily inserted into your own emails.

Rated 4 out of 5 stars (469)
115,304 users

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Woordenboek Nederlands

Dutch dictionary with wordslist from OpenTaal.

Rated 3 out of 5 stars (70)
22,127 users

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Signature Switch

Switch the signature on/off or choose a new one from your predefined set.

Rated 4 out of 5 stars (272)
48,609 users

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Diccionario español Argentina

Spanish dictionary for Argentina.

Rated 4 out of 5 stars (93)
15,149 users

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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 (190)
13,693 users

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Ukrainian dictionary

Ukrainian (uk-UA) spellchecking dictionary

Rated 5 out of 5 stars (58)
10,508 users

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General Catalan dictionary

Free Catalan (general version) spelling dictionary.

Rated 4 out of 5 stars (40)
8,007 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)
9,096 users

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