Slack It - A bookmarklet to share links in Slack with one click
Slack News Feed - Get the top posts from every Slack chat you're in.
Tettra - Tettra is a company wiki that helps teams manage and share organizational knowledge.
Lurchr - Saves all your Slack links, so you can focus on work
Pushpop for Slack - Push your analytics data into Slack
Slack Platform News - News and updates from the Slack Platform direct to your team