Off the top of my head...
First aid kit and the ability to use it
contents depend on ability
bandages
tweezers
antiseptic (alchol pads)
extra meds you take (blood pressure, insulin, etc)
Spare tire
Something to air a tire up with
Tire plug kit
Tools-sockets, ratchet, wrenches, extension, pry bar!, screwdrivers, wratchet straps
Jack base (spread out load if you have to jack on mud/sand/loose dirt)
Blanket
Poncho or rain jacket
Map
Light source
Parts (valve stems/cores, bolts)
Rifle or pistol or shotgun (or all)
Ammo as appropriate
Snacks and water
To get you through the day
CB
Know the channel monitored in the area (33 at Coal Creek)
Recovery gear-leather gloves, shackle, tow strap, tree saver, winch stuff (REMOTE)
blanket for wire line
Axe
I use a gerber camp axe mounted with quick fist clamps
Fire extinguisher
Even the cans from Home Depot are better than nothing
Extra clothes based on conditions (warm for winter, cool for summer)
Charger plugs for your powered accessories
Extra batteries for whatever you have that needs them
Tent
For overlanding also consider the following
Gas
More water
Water purification
Filter, tablets, clorox
More food
More batteries
Signal mirror
Fire starter
Fat wood
or whatever your favorite fire starter is
Map and ability to use it
Chainsaw can be handy but is situational
Fuel for said chainsaw
