Playmoss - Create playlists from YouTube, Vimeo and SoundCloud
Playlist Machinery - Tools that help you create & organize your Spotify playlists
Playlistor - Convert Apple Music playlists to Spotify and vice versa
Audioship - Upload audio to YouTube or Facebook
playAppleMusic.com - An (unofficial) web player for Apple Music
TunesToTube - What does TunesToTube do?