Wandering peddler, an always-peaceful, randomly-generated monster that aimlessly wanders the dungeon. (Possibly, these could be implemented as shopkeepers that are detached from any shop, but that may be too complicated.) Chatting to them causes them to try to sell you items from their inventory, which they generate with several of. The items are mostly those eligible to generate in a general store, but with certain weight and possibly cost caps. Killing them either doesn’t drop their items, or it does but carries the normal drawbacks of murder and having to overcome a shopkeeper-quality monster.

In order to prevent farming items off them through create monster, these might have a low extinction cap of 20 or so.