Argument for the Fae and other undiscovered species

Amazing new discoveries in Anthropology are happening on a weekly basis lately. Evidence of Human habitation far earlier then previously thought. Theoretical physics work that points to the possibility or probability of intelligent design in our universe. Why couldn't creatures thought to be fairytales and labeled as the Fae in paranormal circles be real? Is it so far fetched to think that there could be species of humanoids on our planet that have gone undetected so far? There are gaps in our evolutionary tree, could the whole theory behind it be based on too much conjecture? Are we really the dominant species on earth or are we the Aliens?