Operation Mirror Image: Features background, mecha, and ships for a Rifts-crossover campaign set after the television series.
REF/Mechanoid War: A play-by-email campaign set on the SDF-3 after its disappearance.
Robotech RPG - Mike Perry: Based on the Palladium Books RPG system. Great resource for e-mail campaigns.
Roleplaying Macross: Notes on adapting Macross II rules for use with games based on the anime series Macross Plus and Macross 7.