Parallel - Listen to music with friends over Spotify at the same time
Pandora iMessage App - Say it with Pandora — Send and receive songs in iMessage
Slackbox - Spotify playlist collaboration through Slack
YouTube Music - YouTube Music is a streaming app primarily designed for Android and iOS mobile devices. The app lets individuals search for music from their favorite artists, enjoy playlists, and access 30 million musical tracks.
Join My Playlist - Listen to music live together with your friends in Spotify.
Spotify - Map shows when two people play same song at same time