[@dark light] haha I guess... I mean I'd say that anything that's physically heavier than your character should be able yo be considered (rrference weights on bulbapedia). Then, use common sense. 

Are you just looking for Pokemon that can carry your trainer? Just look for the really big ones like onix. Here's the link to the list of Pokemon by weight: [url]http://bulbapedia.bulbagarden.net/wiki/List_of_Pok%C3%A9mon_by_weight[/url]

I'd say anything over around ~200lb ought to be good. 

Also reference the height list if you want: [url]http://bulbapedia.bulbagarden.net/wiki/List_of_Pok%C3%A9mon_by_height[/url]