Those were just to display what I meant by using a neutral icon. I recognize those are all fairly boring. They're also not pixel art. Yes yes.
But with you saying that, how do you think it would be to use a single gray color and do like a bunch of images from across several different genres, like a spaceship, a platform dude, maybe some classic RPG imagery, etc., all packed into one compact, dramatic icon? The theme being that the icon-less game has the potential to become any number of things.