You could check HE Clinic in Bangkok. They only do
HA, and supposedly they are good at it. I met two of the doctors, and their patient relations officer is a very nice guy! I did not have any filler done there though, but I visited the clinic a couple of times, and I got a very good impression.
Otherwise, I think MegaFill is more common in Korea than
HA. They got at least one other Korean filler too. I believe MegaFill is permanent, and the other one supposedly only lasts for half a year. It might be some kind of domestic
HA filler, I guess?