Read the Gods and Religion section and it becomes clear that even Tiamat and Bahumut aren't "Gods" in the Typical sense, other Gods have their origins in the outer planes, Tiamat and Bahumut have their origins in the Material Plane, the "Gods" of the humanoid races have their origins in the outer planes.
So now we have Primordials that are Elemental Planes Gods, Ester (might have misspelled that term from 4e) the traditional Outer Planes Gods, and now Material Plane Gods, and some Gods that might be Archfey.