Slack News Feed - Get the top posts from every Slack chat you're in.
Right Inbox - Schedule Emails in Gmail To Be Sent Later
Top Daily Hunts in Slack - A simple, fast way to browse news within Slack
EmailPlayground - EmailPlayground provides solution to schedule and send emails with ease.
Slack It - A bookmarklet to share links in Slack with one click
SendLater - Email scheduler for Mac Mail.