Over 200 in total, here's the first half
I hate Hummers so much. Only in America would a car that stupid get that popular. Of course, Forza Horizon 2 has the H1, the actual Humvee-looking one that isn't any less stupid for civilian driving, but at least it doesn't look like a gangly, overgrown Power Wheels like the popular H2 you still see out and about sometimes.
The first 100 cars are listed here.