d20 Future: CODEX GALACTICA
The Ancients known as the Preservers are sometimes theorized to be the same as the Prometheans, but among scientists that don’t adhere the theory of Promethean Seeding they posit that the Preservers are largely to credit with the vast number of very similar species found throughout the galaxy. These researchers point out the number of planets discovered to house Humans, The Fraals, and Elves like lifeforms that appear to have developed out of specific societies. Plus, those that scoff at the theory of the Preservers point out that many of these species are different from humans in subtle, yet important ways that can’t entirely be attributed to environmental adaptations. They suggest that certain society-forms are inherent to similar species. In any case, there is little to no physical evidence to suggest the existence of the Preservers beyond the similarities in societies. As an answer to these questions some theorize that the Preservers were actually a branch of the Prometheans dedicated to the plant “seed” of the human race.
(Taken from Star Trek TOS.)