One I would love to make is a farming/automation game. You start farming on the edge of a forest. Everyone thinks it's haunted and inhabited by monsters. Turns out, that's but actually the case. Sure to the neglect, the resident goddess has lost her powers. As you restore the goddess' powers

And unlock more of the forest, spirits that reside will come help with farming activities. As the monsters inside? They were just desperate animals with a dwindling food chain. Also the forest has four distinct sections, one for every season