mongolians were doing drone before anybody else was
Hell yeah. I love the singing styles from that corner of the world. I don't think I've been around long enough to post links, but I definitely encourage you to look up Aldyn-ool Sevek's "Mountain Kargyraa" performance. I think he gets five notes out simultaneously at certain points in that recording, it's stunning.
I used to have a passable beginner's kargyraa myself, but my false vocal folds are way out of practice.