Minutemailer - Email Marketing. Simplified.
MailStore - MailStore Home - A 100% free single-private-user desktop solution
Mailmeteor - Send hundreds of personalized emails with Gmail.
MailSteward - MailSteward : The Ultimate E-mail Manager for Mac OS X
Visual Marketing Automation - An insanely fast automation builder by ConvertKit
Gmvault - Backup the emails in your Gmail account.