I mean this one kinda is still a sandbox. But the closest I can think of that's on Twine is Fantasy Slave Trainer, but that one is kinda lame to me. It takes 3 thousand years to get anything done, unlike FC the slaves keep fluctuating with their needs since they do get tired after a while. Some might like being on their toes all the time, but I prefer how once you get the right flow going, most of your slaves take care of themselves. I liked it because it was using mystical races instead of just actual races for real countries, though there are still humans, they're considered the basic old slaves. I think there's a bit more hands on time for actually training your girls unlike FC, but it just feels tedious to me.
