Um, does James-class count?

I mean, you do fight him in Let's Go and Yellow. Sure, James-class counts

Nice.

My favorite is James-class xD

I can't remember but I'm really sure there is a clown class and if so then

If not then Hex Maniacs I guess

I go with the Pokemon Breeder Trainer class since those battles have multiple Pokemon. Gave much exp and are Rebattable

Like Brock?

That is a good comparison. My thought was on the Gen 4/Gen 5 trainers of that class.

Oh amazing I know one other thing besides Team Rocket about Pokemon :)

Champion?

Basically any trainer you can fight counts