Thanks Sandman, I'll look for more. I'm familiar with the Tuvan and Inuit varieties, and modern American overtone singing, but never heard of Bulgarian.

Also, questioning collectors has been a thing since I've been on the internet (early 90S), and before that for as long as I remember. As in FJ Child leaving out certain types of song because of reasons. And John Jacob Niles (did he collect it, or did he write it.) If they were around, and enjoyed being trolled, these discussions might go into the millions, except merely the thousands.