In my efforts to update our trumpet jury requirements here at Western, I’ve created a repertoire list. These pieces come from a variety of sources, but most heavily I’ve consulted David Hickman’s excellent book Trumpet Pedagogy (hickeys link) as well as a repertoire list posted online by Luis Engelke here.
It’s not an exhaustive list by any stretch, and grading is subjective, but I’ve tried to include as many works as possible that are accessible to undergraduate students. It’s often very difficult to find repertoire that hits the “sweet spot” between music written for beginners and more virtuosic repertoire (eg: requiring piccolo trumpet).