ITT: We create a game theme that has yet to be created that you'd pay good money to play.

For me, it'd be to play a game that has the same graphics and feel of Stardew Valley, but it's a simulation of the game creator's life in the eyes of the creator, aka you. You'd be able to see the good, the bad, etc. There would be a clock, calendar, thermometer, and other shit like that. Once you get to the creation of the game, you decide how it goes, and you essentially create your own game, play it in a sandbox-esque mode, and the game ends as you play it.