/Favorites - Slick player for Soundcloud favorites
Playlist Machinery - Tools that help you create & organize your Spotify playlists
DaftCloud - DaftCloud is a free and wonderful designed SoundCloud App for macOS.
Playlistor - Convert Apple Music playlists to Spotify and vice versa
Hermes - Pandora Client for OS X
playAppleMusic.com - An (unofficial) web player for Apple Music