Tettra - Tettra is a company wiki that helps teams manage and share organizational knowledge.
Boomerang Respondable - Write perfect emails with Artificial Intelligence
Slinky - Your slack links — organized!
Mailbutler - Mailbutler adds lacking functionality to email clients and increases your productivity
Obie.ai - Access knowledge quicker without leaving Slack
Boomerang for Gmail - Boomerang for Gmail is a Firefox / Chrome plugin that lets you take control of when you send and receive email messages.