I have approx. 10,000 songs across my Spotify playlists, and being as indecisive as I am, I always hate how I've organised them.
Using this site, http://organizeyourmusic.playlistmachinery.com/, you can sort all of your music in one place, by genre, tempo, mood, and abstract quantitative measures like their 'accousticness', amount of speech, 'popiness' and their duration.
You can even plot your music on these attributes and select songs which match your chosen criteria and make new playlists from them.
TIL that the macarena is my least angry and most dancable track, which makes a whole lot of sense 🙏