Let’s say you could have a free license to continue, expand upon, or otherwise develop an existing fantasy/SF property. You could do anything you want with it, but you’d be the producer/show runner/new author. You can’t hire someone else to take it on for you.
My pick is Hayao Miyazaki’s Nausicaä of the Valley of Winds. I would write novels and produce tabletop and video games, but I would never, ever do a manga or anime.
What would you choose?