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.
I don’t carry a headlamp but I keep them around and handy. Very useful for dark corners of the garage and basement. Mandatory for camping.
Hands free task lighting is very useful.