Partyhero - Pass your friends the aux!
Guitarix - Guitarix is a simple Linux Rock Guitar Amplifier for https://alternativeto.
Heartbeat - Listen to music with your friends together, on Spotify
Ampire - State Space Modeled guitar amp/cab/stompbox simulator.
TuneMeet - Chat with people who are listening to the same song
TH-U - World class guitar amps and effects for PC and Mac