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

Novu - The ultimate library for managing multi-channel transactional notifications with a single API.

Recurrr - Send recurring emails

SuperSend.io - Automate Cold Outreach Across Email, Linkedin and Twitter.

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.

SuprSend - Single Notification API for Every Channel (SMS, Slack, Whatsapp, Email, SMS, Push, App Inbox)