Lurchr - Saves all your Slack links, so you can focus on work
Photostash - Automatically save your pictures from Slack to Gdrive
Tettra - Tettra is a company wiki that helps teams manage and share organizational knowledge.
Heymarket for Slack - Text and Facebook messaging from Slack
Slack It - A bookmarklet to share links in Slack with one click
ProductPlan - Cloud-based product roadmap software solution