Pandora iMessage App - Say it with Pandora — Send and receive songs in iMessage
Parallel - Listen to music with friends over Spotify at the same time
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.
Slackbox - Spotify playlist collaboration through Slack
Spotify - Map shows when two people play same song at same time
Join My Playlist - Listen to music live together with your friends in Spotify.