My "Barbarian, Conqueror, King" setting has all sorts of sci-fantasy and weird fantasy elements, from aliens to dinosaurs. However, I was thinking about a way to bring some of these elements to a more "standard" fantasy setting such as the Auran Empire. This will combine elements of the Isle of Dread and of the Expedition to the Barrier Peaks.
The Isle is a large-ish volcanic isle with a tropical climate at relatively remote location from the known world. It has some things "that time forgot" - such as dinosaurs. It also has a large alien starship crashed into its high - and mostly dormant - volcanic caldera and its lake. Local life, then, combines strange prehistoric flora and fauna with some more "ordinary" men and "civilized" lizardmen - and with alien flora and fauna who came with the now crashed ship. There are of course also some aliens around, though they prefer to work from the shadows. The ultimate treasure of the Isle is alien technology, mostly located within the crashed, half-flooded starship.
There are three Neutral human tribes living on a peninsula, as well as a trade station with traders from actual mainland civilization - which is overseas. Local technology is primitive and the locals engage in horticulture and fishing; the trade station offers "modern" standard-ACKS goods, though at a limited supply. Each tribe has its own village with a chief (Fighter or Barbarian from the Companion) and a Head Shaman (Shaman class from the Companion). A crude wall and even cruder fortifications manned by tribal warriors protect the peninsula from the much more savage main island. The locals have some domesticated dinosaurs as beasts of burden, but also raise their dead as zombies to do menial work in the fields.
A fourth Neutral tribe - of "civilized" lizardmen - lives further along the coast, unprotected by the wall but protected by its swampy territory. These lizardmen trade with the other Neutral tribes and with the trade station and their leader is a Witch-Doctor (from my own Barbarian, Conqueror, King rules).
Another pocket of "civilization" further along the are pirates raiding the - relatively new - maritime commerce among the local islands and the mainland. They do have a natural harbor to moor their ships, as well as a cave complex to serve as a camp.
Other than that, the Isle is savage. Several tribes Chaotic cannibals - both men and lizardmen - inhabit the island, as well as countless other monsters, some of them completely alien.
The Isle does have the ruins of an older, somewhat more advanced civilization. It is unclear what is the relation of these ruins to the current-day tribes.
Up on the mountain, a weird fifth Neutral village exists, but they have strange customs and they worship very strange gods. Their actual gods are surviving aliens, and they will deliver captives as "sacrifices" - experimental subjects - to the aliens. Their High Priest is actually a Mage and has several high-tech alien gadgets at his disposal - and his guards carry plasma weapons. Beyond this village lies the caldera and within it the crashed alien ship, broken into two and half-submerged in the caldera lake.
What do you think of these ideas?