Just noticed Frost Children on the bill. I'd never heard of them until they opened for fellow St. Louisians Gravity Kills for their reunion show last fall. I was pretty into it. They're not easy to pin down genre-wise, but I'd imagine fans of the also from St. Louis 100 Gecs would enjoy them.
Graspop taking them would be awful. To be honest as well I see them as a bit different acts. Pendulum would have a lower spot to thus not taking a more likely graspop higher band away like Prodigy would.