Mu4e - Starting with version 0.9.8, mu provides an emacs-based e-mail client which uses mu as its back-end: mu4e.
aerc - Highly efficient and extensible email client for the terminal
Mutt - Mutt is a small but very powerful text-based mail client for Unix operating systems.
Netlify - Build, deploy and host your static site or app with a drag and drop interface and automatic delpoys from GitHub or Bitbucket
Mailspring - Mailspring is a mail client for Mac, Windows and Linux.
Coolify - An open-source, hassle-free, self-hostable Heroku & Netlify alternative.