First thing in the morning, Mundo and Billious meet with Yelid of the Many Hues and learn the results of his research.
From what I can gather, there are a few sources of wealth in the Badlands. The main one is preying on the caravans that travel to Avauntar from the lawless city of Maquan Bay. Spices, salted fish, and pearls come from Maquan Bay, as well as trade goods purloined by the pirates. The Queen turns a blind eye to the origin of these goods and pockets the tax revenue. Luxury items make the trip back to Maquan, but the Queen forbids any arms or armor. I'm sure you could find a few smugglers who ignore that particular Royal order.
There are several tribes of beastmen in the hills that make a fine living as raiders. Mainly orcs but a few ogres and some giants as well. Hill giants but I've heard whispered rumors of a castle full of fire giants. I know of five orc tribes in the Badlands. From smallest to largest, they are the Gaping Maw, the Crooked Moon, the Necksnappers, the Red Blades, and the Blood of Hargosh. The Gaping Maw has maybe 30 orc males, but the Blood of Hargosh has well over 100. Hard to say about the ogres, there's likely to be a village or two up in the hills that no one knows about. But there are the Hilltoppers and the Hungry Ones, that we know of for sure.
More feared are the gnoll reavers. Caring not a whit for trade goods, they come out at night to hunt for human flesh. They feast on the nomads of the Badlands, and won't shy from a fight with centaurs if threatened. Can't say how many gnolls there are. No one knows where their village is, or if there are more than one.
The nomads are your usual sort. Mostly goatherders, they move from place to place, looking for wild fruit and scrub for the goats, hunting the occasional ungulate. They aren't friendly, per se, but aren't actively violent unless provoked. They rarely attack travelers or caravans but will do so to avenge a wrong or if orc and gnoll raids thin their herds. Three or four tribes out there, I think. Hard to say, sometimes food gets scarce and the tribes split into smaller groups every now and again. The Dorset, the Thule, the Kevela are the three big ones. A few hundred each, if you count the women and younglings.
The centaurs are a mystery. Usually found deep in the forest, no one knows what this particular tribe is doing in the Badlands. I'd say they're the key to all of this weirdness. If you want to figure out what everyone and everything is looking for, start with the Chag.