i don't know why people seem to think diversity is such a great thing for a model's portfolio. if you look at an agency model's book, there's not going to be a random mix of shots. there might be 15 photos that are all different, but they'll all be strong commercial photos, or strong fashion photos, or strong glamour photos. not a mix of genres.
if you want to know what to show an agency, the first question has got to be, "what agency?" or, at least, what kind of agency. a commercial agency is not going to want to see the same thing as a fashion agency or a talent agency.
if you can see the portfolios of the models they already represent, then it would probably be a good idea to use those as a guideline.