Always more ammo, can't own enough. Also, something that is overlooked? Parts for the arms you have to repair them in the event of failure/damage. Good water filters and purifiers and depending where you are, storage. Plenty of that "freeze dried survival food". All of the basic meds you can get and things like medical supplies (first aid kits, rubbing alcohol, etc). Extra communication gear, I am not HAM certified but im picking up a few radios to have around. In a SHTF situation people are not really going to give a fuck what your callsign is as long as you can follow basic rules. A battery pack that can be recharged via solar or gas generator to keep things running if needed. Really, these are just things I assume most people should have anyway but don't. Not even going "prepper".