Baritone - Spotify controls that live in your menubar.
Musish - A web client for Apple Music
Soundiiz - Transferring playlists between various music streaming platforms.
feverTunes - A web player for Apple Music support adding tags to playlist
Hologram - Frontend Development and Design
Apple Music - Apple Music app combines your personal iTunes library with Apple's music subscription service. Music you have purchased from the iTunes store, or synced over from other sources, is available in the "Library" tab. Read more about Apple Music.