To a degree, this includes a lot of what I call "A.K.A." monsters, as well--monsters which are basically the same, but different: orcs-hobgoblins-orogs-bugbears (i.e., tough Medium-sized evil humanoids that increase in HD and a few bonuses, for use as grunts against PCs as they level up) are a decent example. Kobolds-goblins-xvarts are another example.
