Who's that Pokemon?さんのイラストまとめ

Also the original canceled third pikachu evolution (Gorochu) had aspects of "Raijin" a god of lightning that Raiju partnered
There are more Pokemon directly inspired by the Raiju myth

Raichu family
(Pokedex 172,025,026)
The designer Atsuko Nishida, said in an interview that Pikachu design is inspired on the japanese daifuku, a sweet filled mochi confection commonly decorated to look like little rodents

Arbok Family
(Pokedex 023,024)
In a lot of myths are snakes with women heads or half of her bodies with the shape of one, poisonous or with the ability to turn anyone into stone or kill just by look at her, like Medusa or Nagas. Commonly despicted partnering other demon snakes

Raticate family
(Pokedex 019,020)
It's usual in fantasy media, incluiding videogames and tabletop rpg to have as a common or weak enemy a giant or pretty vicious rat, the same role this family plays in the first Pokemon games

Pidgeot megaevolution crest is based on the crown Ra and Horus wear when they merge forming the deity named Ra-Horakhty

Pidgeot Family
(Pokedex 016,017,018)
Ra and Horus the gods of the sun and the sky in egyptian mythology manifestated in the shape of falcons with a peculiar face, the same that can be seen in this Pokemon family.
The crest on it's head resembles a pharaoh nemes (The Headgear)

Beedril Family
(Pokedex 013,014,015)
Is classic in fantasy media to have a bee giant monster, this time with a twist making it arms giant spears.
Based on weedle hsting on the head and tail and Kakuna design, i asume it take some inspiration on chinese armours