Shared Spotify - Find the common songs you have between friends
Spot Caller - Find live music events you don't want to miss
Spotify Codes - Share codes for songs, artists, and playlists from Spotify
Gotobeat - Subscription for live music gigs
Bands on a Budget - Economical SWAG meant for bands, often hijacked by startups
music.whassup.dog - Live music on a map