Anime where the main character is OP but hides it 

Sadao Maou From The Devil is a Part-Timer

Gintoki From Gintama

Vash the Stampede From Trigun

Mob From Mob Psycho 100

Yato From Noragami

Luffy From One Piece

Edward Elric Fullmetal Alchemist

Light From Death Note

Naruto From Naruto series

Eren From Attack on Titan

want to read more stories like this