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Mailspring - Mailspring is a mail client for Mac, Windows and Linux.

Forumbee - Forumbee offers community forums for discussions, feedback and Q&A.

Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!

Directly - Directly provides on-demand customer service apps.

The Bat - The Bat! is a secure desktop email client for Windows, designed to protect your correspondence against third-parties and to save your time.