Mailmeteor - Send hundreds of personalized emails with Gmail.
Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
GMass - GMass allows you to easily schedule emails, send out mass emails and mail merge campaigns and more with Gmail! Click here to learn about more features!
Mailbird - Mailbird is the best email client for Windows 7, 8 and 10
Email on Acid - We make the send button safer. For every campaign, every message, and every inbox, Email on Acid has the time-saving tools you need to put your best email forward.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.