An article from 2014, but new to me. At one point in my life, this would have been a dream job: Cataloging and organizing all the genres of music. I bet it would be great to have a beer with Glen.
Most of these are just functional; like “traditional rockabilly”, or “atmospheric black metal”. There are a handful of more creative ones I just made up; my favourites include “fallen angel” and “laboratorio”. I try to only do this when there are no good existing options. But hey, somebody has to name these things.