Here's one thought for an interesting setting:
The corebook describes a human colonization effort on a new planet. The planet has unusual heavy metals that the colony hopes to one day exploit. These rare earths also seem to be increasing the prevalence of psionic powers amongst the colonists, especially among the native-born.
The first setting supplement details another continent on this planet, which is actually a fairly typical fantasy setting with elves and orcs. There is even a human kingdom here, which started when one of the colony ships crashed on this continent. I was tempted to put in something completely different and fantastical, but I had a really cool idea of an elven mage piloting a tree like a mecha/treant and fighting against a human, purely technological mecha and I want that in the setting somewhere. This supplement will contain all of the magic rules and suggestions for what happens when the colonists move to this continent and interact with the fantasy races there.
Second setting supplement is a slightly more distant colony ship that landed near a particularly concentrated deposit of heavy metals. This colony is somewhat more established because some of the people have been developing unusual physical abilities which have helped immensely in terms of construction and resource gathering. This setting is much more urban and (you guessed it) has superheroes and villains among the population.
From here we can go off-world to see what sort of galactic culture exists, what alien races are out there and what sort of adventures can be had in this universe.