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Provider for Google Calendar

Allows bidirectional access to Google Calendar

Rated 3 out of 5 stars (1,650)
182,742 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.

V3.3.3 has 140 000+ new words and also fixes.

Rated 5 out of 5 stars (83)
162,572 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)
68,697 users

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German Dictionary

German Dictionary (new Orthography) for spellchecking in Mozilla products

Rated 4 out of 5 stars (82)
224,698 users

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Spanish (Spain) Dictionary

Spanish/Spain Dictionary

Rated 4 out of 5 stars (167)
58,741 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 (445)
65,648 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 (226)
64,061 users

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DKIM Verifier Featured

Verifies the DKIM-Signature of an e-mail.

Rated 4 out of 5 stars (45)
17,521 users

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Dizionario italiano

Add support for Italian to spellchecking

Rated 4 out of 5 stars (71)
71,586 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)
98,213 users

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Woordenboek Nederlands

Dutch dictionary with wordslist from OpenTaal.

Rated 3 out of 5 stars (70)
22,452 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)
50,089 users

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Lightning Calendar Tabs

Displays tabs which allows quick navigation between time periods in Lightning calendar. All views of calendar are supported. Color of tab texts can be adjusted.

Rated 4 out of 5 stars (24)
27,690 users

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Diccionario español Argentina

Spanish dictionary for Argentina.

Rated 4 out of 5 stars (93)
10,789 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 (187)
14,508 users

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Ukrainian dictionary

Ukrainian (uk-UA) spellchecking dictionary

Rated 5 out of 5 stars (57)
10,609 users

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General Catalan dictionary

Free Catalan (general version) spelling dictionary.

Rated 4 out of 5 stars (40)
12,113 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)
9,178 users

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Emoji

Add emojis to your e-mails.

Rated 4 out of 5 stars (64)
23,795 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)
23,617 users

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