Off the top of my head I have chargers, sunglasses, brufen, snacks/water/hand gel, a giant umbrella, assorted maps and a compass, a change of clothes or two, boots, IFAK, shovel, a couple of flashlights and some tools. Most of these things are used frequently enough that it would be massively annoying not to have them, and some if you need them then it’s too late to get them from somewhere else.