oop... also tampons (sterile) can function as many devices ( chest tube, pericardial tube, etc..) also cotton is a fire starter

All depends on what you need/want. Modern days, life saving stuff... you need an 10 blade (finger thoracostomy), some smart device (phone usually does), a light, and a pen. Yes, Diphenhydramine (Benadryl) would be nice, aspirin as well. But hell an epi-pen would be even better. A tuning fork, relfex hammer, etc..…