I'm convinced down to my bones that the best way to get rich in a post-mamono world, other than opening up a dating service, is to sell monster girl-friendly furniture. Like, let's disregard the fact that so many different monster girls are considerably bigger than regular-sized humans (dragons, oni, hellhounds, etc.) or have physical shapes that no way adhere to the human body plan (weresharks, lamias, etc.) even roughly human-sized and human-shaped mamono are in need of furniture that can stand up to their monstrous physiques. Just take the mad hatter in the pic at the top of the thread; do you believe that there's a single chair sold in stores that could stand up to the sheer quantity of her enormous ass, or a single bed that could withstand the sheer force of her screwing some guy's brains out without being reduced to splinters? No, you need a better grade of furniture for that, and you'd make a shit ton of money if you did so.