Heartbeat - Listen to music with your friends together, on Spotify
Subsonic - Subsonic is a free, web-based media streamer, providing ubiquitous access to your music and video.
Partyhero - Pass your friends the aux!
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.
Vertigo - Vertigo is a web and Android application that allow you to listen to music with friends in real-time.
Ampache - Web ( HTTP centralized ) based audio/video streaming application