Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Mailbox for Zoho - Multi-Account Zoho client for Mac.
Mailbird - Mailbird is the best email client for Windows 7, 8 and 10
Columba - Columba is an email client written in Java, featuring a user-friendly graphical interface with...
Mailspring - Mailspring is a mail client for Mac, Windows and Linux.
EmailTray - EmailTray is an email client and an email notifier for Gmail, Hotmail, Yahoo mail and AOL. EmailTray ranks messages and alerts you to the most important ones.