Made for Windows 10/11.
If you browse through lots of custom songs in Beat Saber, you may eventually be left with a large amount of song files that are not included in any playlists anymore.
This script will delete any song folders that don't have the corresponding song key in any of your playlists.
Place the script in the root of your Beat Saber folder, and run it with python.
Some playlist entries do not include a song key. (Older format?) These will not get detected. Any such unintentionally deleted songs can be easily re-downloaded in-game though. Your playlists will not be altered.
Make sure you have a backup of Beat_Saber_Data/CustomLevels before proceeding!