Playlist Machinery - Tools that help you create & organize your Spotify playlists
Plug - Lightweight OSX player for Hype Machine
Magic Playlist - Get the playlist of your dreams based on a song
SonicRoad - Discover great music faster than ever before
Vinyls - Vinyls is a music player that lets you listen to your music without any complicated setup.
Playlistor - Convert Apple Music playlists to Spotify and vice versa