Mailspring - Mailspring is a mail client for Mac, Windows and Linux.
Geary - Geary is an email application built for GNOME 3.
Airmail - Airmail is a lightweight and lightning fast mail client for Mac.
Mutt - Add forums and commenting to your site. Unlimited posts, users and traffic, for free. Embeddable, styleable and scriptable.
Trojitá - Trojitá, is a fast Qt IMAP e-mail client that respects open standards and facilitates modern...
Nextcloud Mail - 💌 Mail app for Nextcloud