Momixa - Pick two songs and get the perfect mix
MusicTwin Finder - Find your MusicTwin by your Spotify playlists in 5 seconds.
Music Suggestions Ninja - Enter an artist's name & find similar, lesser known artists
SoundCloud Charts - The most played tracks on SoundCloud this week
Boil the Frog - Create a seamless playlist between any two artists
Playlist Machinery - Tools that help you create & organize your Spotify playlists