Tettra - Tettra is a company wiki that helps teams manage and share organizational knowledge.
Slack It - A bookmarklet to share links in Slack with one click
Slinky - Your slack links — organized!
Paperbot (Reloaded) - Slack meets Pocket
Obie.ai - Access knowledge quicker without leaving Slack
Clearbit for Slack - Send all signups directly to a Slack channel