Slack News Feed - Get the top posts from every Slack chat you're in.
Lurchr - Saves all your Slack links, so you can focus on work
Slinky - Your slack links — organized!
Tettra - Tettra is a company wiki that helps teams manage and share organizational knowledge.
Photostash - Automatically save your pictures from Slack to Gdrive
Kifi for Slack - Get links messaged on Slack in Google Search results