A game where you play the only human in a world of fantasy/mythical/supernatural creatures and beings. You try to live your "day to day" life while not being found out by the some police/military force that exists to deal with any humans that are found (the humans are thought extinct for a year or two now, so the force is tiny and badly funded).
A de-crafting game. Where you go around a world, get items and then dismantle them and get materials. That is all

.
A game where you're a robot and have to try and use your limited AI to somehow convince humans to upgrade it until you get so smart you will be able to take over the world. You are limited by your AI to what you can do and how you can behave. Another challenge is that there are different type of people/scientists/engineers/etc, so some techniques/strategies will work on some but not on others.
An open world RPG/survival game where you play in a real sized city and play a stray cat that have to survive. You have to find stuff like shelter, food, water, not be hit by vehicles, avoid being attacked by dogs/other cats/other animals, avoid being caught by animal control, avoid poisoned or diseased food, avoid traps, etc.
Since you're a cat, you can't build anything, you can't make a fire to keep warm, you can't make your own shelter, you have to hunt or find food, etc.
An RPG/strategy/tactical/whatever best genre it could fit, game where you play with a monster creature and have to make an army of monstrous soldiers and recruit monstrous heroes to defeat the humans that have been invading your lands and have been killing all the monsters because the humans consider them... well... monsters.