Sunglasses. Sometimes the sun will be at just the right angle to blind you, and the sun shade won’t help.

Advil or Tylenol or something like that. Especially handy if you forget the sunglasses.

Pesto Bismol, some antacid tablets, etc. It’s possible that one of those those new restaurants or gas station snacks won’t agree with you.

Toilet paper. Just because someplace has a toilet doesn’t mean it’s well equipped. Also useful if there’s NO toilet, but it’s an emergency.