There used to be some opendirectory posts that had some weirdly unsecured files if complete stand ups. You’d have to chip them down for tracks and metadata but it was a fair amount of 80s - 90s albums.

Honestly, I'd try slsk (through the program nicotine+ ideally). There's shit up there that I'm straight up surprised to find quite often, just make sure to put like 1,000 files (can be almost anything, fr) in your share folder before you begin downloading or the bots will get ya, and hope that the only copy isn't from some cocksucker that [Private]s all his files for trades like a true scumbag (also, if you see those people, ban them from your files. However If they just mark [Private] and don't specify trades, they may just add you if you PM them and are sharing stuff yourself, those guys are ok). I also put my downloads folder in my share folder to just automatically re-share everything I get until I need to clear space (unless I choose not to reshare a file and I save it somewhere else of course). You can also set a wishlist in case someone with a file matching your description comes online at a later date if you can't find it right then.

If you're looking for a few specific ones I can check a couple to see if they're up there real quick, no problem.