So, in the pokemon Games, there are just...

People who know Pokemon Moves.

The Move Tutors, they... Seem to know the moves.

Like, the guys who teach Mega Punch and Mega Kick in Gen 1 are martial artists specialized in Punching and Kicking. The Dream Eater tutor is a guy who knows how to eat dreams after dreaming about his dream being eaten.

Not a tutor, but the manager at the Kanto Power Plant in Gen 2 claims to be so mad he can blast things... And Acts like he himself is the one who can use Charge Beam.

Was that ever explained? I don't think you see that talked about very much.