Daily Yo-kai Watch Factsさんのイラストまとめ

Slurpent is based of off "Yamata no Orochi", a creature from Japanese folklore. "Yamata no Orochi" is an eight-headed serpent, and is the Japanese equivalent of a hydra. Slurpent has eight tongues to represent this, along with an eight on his chest, head, back, and tail.

Maiccaa GOGO is a variant of Oh Wheel that originates from Yo-kai Watch World. Maiccaa GOGO has a sticker on his windshield that says, "Oh Wheel". This is the only instance in which a non-localized variant of a Yo-kai has acknowledged its original counterpart's localized name.

Peachnyan, Duriannyan, and Coconutnyan are three unreleased Yo-kai that were discovered within Yo-kai Watch World Memories' Yo-kai Medallium. They are suspected to have been part of a Fruitnyan event that was ultimately scrapped due to the shutdown of Yo-kai Watch World.

Intrudapyon is the only Yo-Criminal to have been designed by a fan.

In episode 91 of the Yo-kai Watch anime, Whisper briefly sports a white jumpsuit and pompadour, likely an homage to American singer and actor, Elvis Presley, who would commonly wear a similar outfit at his performances in the 1970s.

Salarynyan S is the mascot character for LEVEL-5's sales account on Twitter. Salarynyan S's only appearance in official media is as an NPC in Yo-kai Watch World.

Da Vincibana's Soultimate Move from Yo-kai Watch: Puni Puni shows a graphic of what resembles the Vitruvian Man, a drawing by Leonardo da Vinci, who is also who Da Vincibana is directly based off of.

Flamurice's appearance and Japanese name (焼きおに斬り/Yakionigiri) are based off of grilled rice balls, but his Japanese name is also a pun on "onigiri", which although primarily means rice ball, おに (oni) can be interpreted as "demon" and 斬り (giri) means "slice".

Yo-kai Watch Land, he is referred to as Buffoom. (2/2)

Yodelsen is the only Yo-kai as of this time that is directly based off of the Yo-kai Medallium. Not only does Yodelsen’s main body reside within a book, the staffs that Yodelsen wields resemble the first 8 Yo-kai Tribes’ symbols, and are in the same order as the Yo-kai (1/2)