This looks great. As a fan of dark maps I really like when the "feel" of an area can be represented...in this case a dark and spooky swamp. I need to know what sort of general scale yer lookin at here before I can help ya with yer list. If those are intended to be mountains instead of rocky outcrops, then I'd say scale is quite large so I'd say the fleshing out would consist of roads and cities with some sort of texture on the water maybe. If they are just sort of rock totems piled up by the people then you could go full on with houses, carts, canoes, etc. and some junk in the swamp like deadfalls, snags, moss, etc. and a few gators.