In the type system used by Super Smash Bros. Brawl, the throwing type is what all throws are considered to be. Throws cannot be assigned any type other than this one, though they can be given various effects. Regular hitboxes can also be assigned the throwing type. In the Subspace Emissary, throwing attacks can be boosted by [Throwing] Attack stickers.
In Super Smash Bros. Brawl
List of hitboxes with the throwing type