NeverBounce - Real-time email verification and cleaning to ensure emails never bounce.
SendRecurring - SendRecurring allows you to setup, send, and maintain scheduled email reminders.
Email List Verify - The Fastest Way to Improve Email List Deliverability and ROI
Recurrr - Send recurring emails
clearout.io - Clearout Email Finder & Email Verification Service - Drive sustainable business growth by expanding your reach, lowering hard bounces, and improving deliverability rates.
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.