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Provider for Google Calendar

Allows bidirectional access to Google Calendar

Rated 3 out of 5 stars (1,654)
178,363 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)
157,932 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)
65,106 users

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German Dictionary

German Dictionary (new Orthography) for spellchecking in Mozilla products

Rated 4 out of 5 stars (82)
219,742 users

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Spanish (Spain) Dictionary

Spanish/Spain Dictionary

Rated 4 out of 5 stars (167)
53,733 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)
63,777 users

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DKIM Verifier Featured

Verifies the DKIM-Signature of an e-mail.

Rated 4 out of 5 stars (47)
18,527 users

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Dizionario italiano

Add support for Italian to spellchecking

Rated 4 out of 5 stars (71)
68,187 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)
98,278 users

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Woordenboek Nederlands

Dutch dictionary with wordslist from OpenTaal.

Rated 3 out of 5 stars (70)
22,245 users

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Thunderbird Conversations Featured

This addon provides a conversation view for Thunderbird, grouping messages together and allowing you to reply "inline" thus providing a more efficient workflow.

Rated 4 out of 5 stars (560)
24,448 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)
51,231 users

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Diccionario español Argentina

Spanish dictionary for Argentina.

Rated 4 out of 5 stars (93)
13,228 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)
14,072 users

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Ukrainian dictionary

Ukrainian (uk-UA) spellchecking dictionary

Rated 5 out of 5 stars (58)
8,420 users

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General Catalan dictionary

Free Catalan (general version) spelling dictionary.

Rated 4 out of 5 stars (40)
10,969 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)
8,904 users

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Emoji

Add emojis to your e-mails.

Rated 4 out of 5 stars (64)
23,357 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)
8,823 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 (71)
13,666 users

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