Boomerang Respondable - Write perfect emails with Artificial Intelligence
Obie.ai - Access knowledge quicker without leaving Slack
Mailbutler - Mailbutler adds lacking functionality to email clients and increases your productivity
SlackScreen - Full screen public Slack channel display
Boomerang for Gmail - Boomerang for Gmail is a Firefox / Chrome plugin that lets you take control of when you send and receive email messages.
Tight - A Chrome extension that simplifies the Slack interface