Beans, my friend, although I suppose gas-causing input is a fairly personal matter. Beans will get me anytime, but for a burger to do the deed, it needs to be rare.
Perhaps someday, someone from S. Africa will start a thread around what foods, or mixtures of foods, produce the most noxious effluvia.
Were such a thread to be started, I’d try to be first in with the nomination of egg salad sandwich, fresh pesto, and a garlic dill. Or really anything involving garlic or eggs.