Anna's Archive backed up Spotify.

Anna's Archive backed up Spotify. They got 99.9% of metadata, and 300TB of music representing 86 million tracks - original 160kbps OGG for tracks with popularity>0, and re-encoded 75kbps for popularity=0. absolutely wild project.

the metadata in particular is a hugely useful data source. MusicBrainz catalogues 5 million unique ISRCs (like ISBNs but for music releases), whereas this archive has a whopping 186 million.

https://annas-archive.li/blog/backing-up-spotify.html