Maintaining that for potentially 100s of files still sounds kind of like a nightmare. Couldn't the sorting/grouping be largely reflected by the folder structure? For example if I put a goblin on a layout I need all sounds that belong to the goblin which are all sorted in "enemies/goblin/..."
If I then had access to this folder structure I could just loop through all files inside that folder without having to maintain an extra list. I can do that additionally if I need to though or even tack on some extra files if needed.
But even getting an array of all files would suffice though since I can just run a filter over it to get all the file paths that contain "enemies/goblin/" and loop over that.