SlackPass - Subscription access to anything with Slack
Spectrum - Browser-based app to visualize the frequencies of an audio file.
Magik for Slack - Magik enables founders, marketers & community builders to create the community experience they never knew was possible.
Roomvine - Chatrooms for real life venues, neighborhoods and events
Community Inviter - Auto invitations for Slack
Treadie - Create your own micro-social network for topics