Youtube-DJ - Mix YouTube songs together
Slackbox - Spotify playlist collaboration through Slack
PlayDeck - A DJ Player in browser 🎶
Playlist Machinery - Tools that help you create & organize your Spotify playlists
Edjing - Discover edjing and edjing Pro, the most powerful DJ apps for music lovers! Mix on Android, Windows and iOS devices and record then share your DJ sets!
Exportify - Export your playlists from Spotify