mailsend-go - mailsend-go is a command line tool to send mail via SMTP protocol, written with golang.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
CMail - CMail is a free Windows command line mailer with advanced message formatting options.
Mailbird - Mailbird is the best email client for Windows 7, 8 and 10
blat - Blat is a small, efficent SMTP command line mailer for Windows.
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.