Clearbit for Slack - Send all signups directly to a Slack channel
Slack News Feed - Get the top posts from every Slack chat you're in.
Google Drive to Slack - Slack notifications whenever you work on Google Drive docs
Slinky - Your slack links — organized!
MovetoSlack - Migrate from MS Teams to Slack in 5 minutes
Tettra - Tettra is a company wiki that helps teams manage and share organizational knowledge.