I carry a powerbank and various USB C adapters so if someone’s device dies I can help them out. It is a lot cheaper and smaller than carrying around seven different cables.
On top of that I carry Tylenol and bandages.
I used to carry a full first aid bag but kept forgetting to restock on supplies.
At one point I had what we called the commuter chain saw. Battery operated with a 6in bar. Kept it in the side trunk pocket. Only need it once or twice a year, but it beats hiking to the house and carrying a full one back. Especially since trees don’t fall across the road during nice weather.