1. Wildspace is made up of four things: planets, stars, crystal spheres, and everything in between those.
2. Whole universes with their own planes, material and otherwise, float in Wildspace in crystal spheres. Crystal Spheres hold entire campaign settings (for example: Middle Earth would be in one crystal sphere, Star Trek would be in another, etc.)
3.
A Spelljammer is any ship capable of space travel. The name comes from The Spelljammer, a giant manta ray-like ship the size of a moon. It is a bustling multi-layered city that gets more impoverished the lower you go.
4. Technology from the mysterious and ancient space-faring species known as the Makors can be found across many planets and even some crystal spheres. Mysterious creatures known as Keepers can sometimes be found wordlessly repairing and tending to their machines.
5. The Gwyndalin Federation is a fascistic and oppressive regime that wants to be the biggest kingdom in all of Realmspace. It'll have to compete against the xenophobic zealotry of the Holy Elven Empire and the militaristic Lunari Union.
6. Thousands of years ago, a mysterious 600-plus year long gap of memories and historical records affected seemingly every planet and species in Wildspace in an event known as The Gap. The Starfinder Society has tasked themselves with uncovering as many details about The Gap as possible.