About

Pokemon Fan Teams is the practice of taking a character (or even real person) from outside of the Pokemon fandom and making them a trainer, then figuring out what Pokemon would be on their team; usually they are chosen based on the character's personality, appearance, interests, skills or plot points.

A popular example being Feriowind's Pokevengers drawings:

This process also is popular in fanfiction, videos and even fan games; where they can be expanded into an alternate universe (AU) where Pokemon exist in a fandom where they are not originally from.