Zendesk Support Suite - Zendesk Support Suite is a tool that solves and emerges multiple tasks in one place.
SndLatr - SndLatr is a Gmail plugin that makes it easy to schedule emails to be sent automatically at a later time.
Gmelius - Gmelius is the first collaboration platform designed for G Suite and your company's daily tools.
SendLater - Email scheduler for Mac Mail.
Google Voice - Google Voice gives you one number for all your phones, voicemail organized in an email format, free...
Right Inbox - Schedule Emails in Gmail To Be Sent Later