SoundMate - Enjoy SoundCloud from your Mac's menu bar
Playlist Machinery - Tools that help you create & organize your Spotify playlists
Tangerine - A beautiful full-screen SoundCloud player
Playlistor - Convert Apple Music playlists to Spotify and vice versa
NOISESUPPLY - Pandora for SoundCloud
playAppleMusic.com - An (unofficial) web player for Apple Music