An underlying assumption is running in these questions. Everything does not originate from Golarion. Golarion is the primary source for the adventure paths/Starfinder Society adventures. For personal campaigns, however, it depends on your gamemaster.
As already stated by some of the comments, ratfolk and elves came from other worlds. Nothing prevents a tiefling from another world being around, for instance. Depending on the campaign, that tiefling may be rare or common.
Again, the gamemaster makes the call. I don't think Paizo will need to restrict a thing on this. The only restriction, honestly, is 'official stats' aka the Alien Archive, or deciding what third party supplement your gamemaster incorporates into the campaign if not making the stats up on his or her own.