SendLater - Email scheduler for Mac Mail.
If No Reply - Simple email automation that works for Gmail
Right Inbox - Schedule Emails in Gmail To Be Sent Later
Boomerang Premium - Schedule email to be sent later, now w/ Premium features
SndLatr - SndLatr is a Gmail plugin that makes it easy to schedule emails to be sent automatically at a later time.
SenpAI.GG - AI-based personal gaming assistant