The Worlds of Wonder boxed set included Chaosium's Basic Role-Playing System booklet
and three game settings designed for use with it: Magic World, a fairly generic fantasy world
resembling a stripped-down version of RuneQuest, Future World, with military
characters a la Traveller, and Super World, a superhero rolegame that was
even published in a stand-alone version.
Steve Perrin, the author of Worlds of Wonder, has created his own rolegame called SPQR. Please check it out!
Also, Steve Perrin's Worlds of Wonder was translated in Sweden as Drakar och Demoner and gave birth to a whole series of rolegames.