Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Outlook4Gmail - Outlook4Gmail provides easy synchronization of your Outlook and Google accounts
Mailbird - Mailbird is the best email client for Windows 7, 8 and 10
Boomerang for Outlook - Boomerang for Outlook offers email productivity tools to track, schedule and send mails at the right time.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
BlueMail - BlueMail is an email management app for Android, iOS, and Windows.