Slackbox - Spotify playlist collaboration through Slack
PartyWith - Connecting people who love to party - anytime, anywhere.
Partyhero - Pass your friends the aux!
Party with a Local - Party with a Local is a free app that connects travelers with locals that want to party.
Songmash - Create playlists with music that you and your friends love
Party Bot - A bot that helps find the best parties happening near you.