wow amazing little wiki here!
you guys are welcome to copy the pages from the Edgar Rice Burroughs/John Carter wiki
there are many races native to barsoom/mars, venus/amtor, va-nah/luna that most definitely qualify as aliens!
Edgar Rice Burroughs was one of the grandfathers of science fiction, so his races definitly deserve a place here :D
I dont know if the pellucidar races count though, since they are from the center of the earth in a speculative version of the earth.