Geniuslink - Build intelligent links that automatically route consumers to the place they're most likely to...
Playlist Machinery - Tools that help you create & organize your Spotify playlists
Coverify - Create your own custom cover art for Spotify playlists.
Playlistor - Convert Apple Music playlists to Spotify and vice versa
Replace Cover - Create beautiful cover art for your Spotify playlists
playAppleMusic.com - An (unofficial) web player for Apple Music