Email clients

Mailspring – free and open source, multi-platform fast desktop mail client

KMail is a free and open source email component of Kontact, an integrated personal information manager from KDE

Sylpheed is a free and open source, multi-platform, simple and lightweight email client

Evolution is a free and open source application for managing personal information: mail, contacts, calendar, tasks, and notes

Claws Mail is a free and open source, lightweight and easily customizable email client and news reader based on GTK+

Geary – simple free and open source email client for GNOME with the necessary set of functions for comfortable work with

Thunderbird – free and open source cross-platform email, news, and chat client, and when installing the Lightning extension, and with a calendar