Current's I know:

Deco27

Pepoyo!!!

Oster project!!!!!

Masa

Nakiso

MITCHIE M IS THE BEST!!

Hitoshizuku-p

Yama-p

Maretu

Kikuo

Mikito-p

Owata-p

Wowaka

Hachi (even tho they don't do vocaloid music anymore)

Akuno-p

And giga

there's more but like... Could you guys give me some underrated producers?!