I love a good chili dog with cheese and raw diced onion.
A polish dog with brown mustard, mayo, and kraut with or without onions.
Regular hot dog: mayo, mustard, dill relish, onions, tomato slices.
My grandmother used to split the hot dot, stuff it with cheddar cheese, wrap it in bacon and cook them in the electric skillet until the bacon was crispy.
Actually, I'll put almost anything on a hot dog BUT catsup and sweet relish.
Usually though, mustard, mayo, and dill relish.