Probably one of those obscure local laws passed in 1835 that Grit or Reader's Digest used to exploit as cheap humor. Like, you can't whistle underwater on Sundays. Or you can't sell ice cream backwards when it's bat season. That sort of thing. Even then, only the madman can be absolutely certain.

He hadn’t illegally bombed a civilian nuclear facility… until a few minutes ago.

Download a car.

Isn't suicide illegal?

It’s impossible to prove a negative, so this would be limited to crimes it is logically impossible for him to have committed. Because, face it, you can’t quite be sure he hasn’t committed cannibalism or whatever.

Driving while talking on the phone. He doesn't drive himself.

• Writing potato with an e.
• Wearing double denims.
• Wearing all purple.
• Jaywalking, at least not publicly.
• Appointing his horse as secretary of state.
• Sending people into pits of wild animals or have them participate in gladiator games
• Cancel your favorite tv series
• Make a portrait of himself in the nude
• Saying "Click the bell to subscribe to my channel" and make click and bell noises during one of his speeches.
• Figuring out but not explaining how the three sea shells work
• Order a pineapple pizza
• Falsely accusing a woman of rape
• Crossposting