Creatures you may find in the Desert

You may encounter Genies, Dao, Efreeti, Brown Dragons, Blue Dragons, Drakes, Serpents, Giant Sand Worm, Lizards, Phoenix, Elementals, Dust or Sand creatures, Medusa, Mummies, other undead, Roc, some fiends.
Otung warriors live in the desert
There is also an ancient human civilization that is in decline at the moment and it had pyramids similar to those of Egypt on Earth