Bronc halters are usually used by western riders and are usually blingy or eye catching, all kinds of decorations and stuff. The "bronc" piece is the wider nose band instead of the thinner piece across the nose.
Oh Sky once had one that was just plain leather and tooled very fancy. I didn't like it though.. he has a large head already so it looked strange on him. But some of those pictures, the horses look fabulous! Especially the teal lines one.