Recurrr - Send recurring emails
Fantastical 2 - Fantastical, the Mac calendar app you'll enjoy using. Quickly create new events with natural language input and more.
SendRecurring - SendRecurring allows you to setup, send, and maintain scheduled email reminders.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
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.
Morgen.so - All-in-one Calendar, Tasks & Scheduler. Morgen is the single hub for everything that revolves around time management.