There has been some minor representation from G-Gundam. Nobel gundam was in an early episode. Maxter Gundam was in the race. In the opening, a Master Gundam variant is one of the silhouettes. I doubt you will see much more than that though since this show ignores other series gundam abilities. None of the G-Gundams could achieve hyper mode since this show follows the use of Plavsky Particles.