Lol Orochimaru sure gets demonized and pwned a lot in and out of the narutoverse.
Let's see if I can remember some...
Well as many I'm sure know now, Hagoromo and his six paths are based off the Buddha Siddhartha and the six realms of reincarnation.
Gai and Lee's concepts are based off Bruce Lee.
Other abilities of the sharingan named after the shinto gods are Kagusuchi, Tsukuyomi and Amaterasu. Amaterasu is the sun god. Tsukuyomi is the moon goddess and Kagusuchi I believe is their child who died.
I hear the seven swordsmen of the mist were inspired by the tale of the seven samurai
Chiyo's puppets are based on a real puppeteer's marrionets and play.
Kurama was also a supporting protagonist from the manga and anime Yu Yu Hakusho, though I believe he originated from japanese folklore.
Ino shika cho was a giant pig in Dragon Ball and also possesses its own folklore.
Sasuke's statue appears to resemble Shiva while Naruto's of course an Asura.
The Susano'os resemble the dogs demons of shinto called tengu
Kaguya is based off a folklore about a goddess of the moon.
Danzou's Baku summon is based of a spirit from japanese folklore that devours dreams and nightmares.
The bridge named after Naruto at the start of the manga is a real bridge.
Hanzo is based off the ninja and samurai hanzo hattori of the sengoku era.
The shinigami is based on a Hannya demon from Japanese folklore and shinto.