Indra_effect7020
Maybe check some older manga and anime, a lot of the inspiration for creatures in those came from Japanese mythology and folklore, like the tricky tanuki (the actual raccoon spirits, not Shukaku from Naruto), you could also look into things like card games. I know Yugioh! and Magic the Gathering have loads of creatures to choose from (especially Magic, check out Kamigawa sets for Japanese-styled creatures). Yugioh! even has a yokai themed archetype called the Mayakashi you can use.