SendRecurring - SendRecurring allows you to setup, send, and maintain scheduled email reminders.

Komiko - Komiko is a sales intelligence solution to drive sales, retention and expansion.

Recurrr - Send recurring emails

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!

Followup.cc - FollowUp for email is a lightweight productivity suite that keeps your conversations and tasks from slipping through the cracks. Set perfectly timed reminders that arrive at the top of your inbox, right when you need them.

mailmark - Send emails and know when they were opened. Keep detaile email logs to who they were sent and when.