Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Mailbird - Mailbird is the best email client for Windows 7, 8 and 10
Zimbra - Zimbra is trusted by over 500 million users to increase productivity with a complete set of collaboration tools while maintaining total control over security and privacy.
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.
Epsilon DREAMmail - Epsilon DREAMmail is the email marketing platform that provides IT services in the best way possible and gives you a fast-growing cloud-based module for easy integration of your business and getting quick market lead and recognition.