Nexusmods user Macadaynu created a mod for Daggerfall Unity that controls an instance of Spotify running in the background and utilises playlists for music within the game.
https://www.nexusmods.com/daggerfallunity/mods/238
Below I list the Spotify playlists I’ve created for personal use in the game. The numeric IDs for these (which you can get from the sharing button) need to be added to the json for the mod. Instructions are in the above link.
Obviously this requires a Spotify Premium subscription. Some tracks are unavailable as I originally started these by adding my local copies of the Lord Braathen and Pieces of 8-bit Daggerfall soundtracks which sadly aren’t publicly available on Spotify. I’m still adding to the playlists over time.
For the sake of disclosure I should add that there are other playlists on Spotify that people have made for use in DFU. Your tastes may vary.