nmail

nmail is a terminal email client for sending, receiving and managing emails directly in the terminal.

Key features of nmail include support for multiple email accounts, themes, signatures, draft messages, composing emails while offline, multi-threading support, compatibility with IMAP and SMTP protocols, email threading for organized conversations, searching and filtering capabilities and integration with external text editors like vim or emacs. This tool also has a simple setup wizard for connecting your Gmail, iCloud, Outlook and other email providers and you can write your email messages in markdown.

Ideal for system administrators, developers and for those who prefer doing email in the terminal, nmail is a lightweight client with a lot of modern features, it is available on macOS and Linux.