Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Mu4e - Starting with version 0.9.8, mu provides an emacs-based e-mail client which uses mu as its back-end: mu4e.
Mailbird - Mailbird is the best email client for Windows 7, 8 and 10
Mutt - Mutt is a small but very powerful text-based mail client for Unix operating systems.
eM Client - eM Client is a fully-featured email client for Windows and macOS with a clean and easy-to-use interface. eM Client also offers features for calendars, tasks, contacts, notes, and chat.
Mailspring - Mailspring is a mail client for Mac, Windows and Linux.