Slack App Directory - Your go-to for finding apps that work with Slack
Usersnap - Visual Feedback - Usersnap helps your business with its versatile feedback platform to build better, more successful products and services with the help of user feedback. Collect feedback along your product development lifecycle. Try it for free.
Clerk Chat - SMS for Slack
Feedback by Pixelic - Painless design feedback and version control.
Cato - Instant Spotlight-like search for your web browser.
Sesov - A community for anonymous design feedback