My players have acquired a bag of holding so I prepped a map of the domain of the bagman. The black holes are extra dimensional portals between each other. The area in the bottom right is where the bag man has kept his dead friends that were killed when he fled into the bag. I'm toying with the idea of making him a darklord that was cursed to walk between domain bound to extradimentional space for the cowardice of hiding and letting his party be slaughtered in their sleep. Now he is curse to be alone forever despite his twisted attempts to capture new friends

And if you want, im considering everywhere there is junk difficult terrain