It's a little difficult to separate the spare parts from some of the tools for repair
-CV axle/s*
-LBJs*
-TREs*
-UBJs
-radiator cap
-spare tire/wheel (a given)*
-Silicone rescue tape (Versatile: hose repairs, makeshift belts, wire insulator, grip tape, etc)*
-accessory belts
-jb quik weld (saved my butt on more than one occasion)*
-jb water weld
-spare headlight bulb (in case you're out during the night; also saved my butt before)
-tire patch (plug) kit (with a method to inflate tire, again, saved my butt before)*
-u joints (with tail-d-vise tool) or spare rear driveshaft
-valve stems (yes, I watched someone at OX east use a tire deflator for the 1st time and his valve stem shot out across a field, no it was not me)
-spare shock** (for those running 5100 billies up front with unknown c-clip condition post-installation)
-zip ties
-rtv
-permatex 1 minute gasket maker
-at least 1 qt of atf, motor oil, and gear oil (or full quantities for paranoia)
-water or coolant*
-plug wires
-sparkplugs
-maf
-air filter
-tps
-fuses
-relays
-all the tools needed to R&R above mentioned
-scangauge2 or other computer code scanner for diagnostics
-digital multimeter for further diagnostics
-a repair manual electronically saved on your portable device or a hard paper copy
-smartphone or tablet with an internet connection to get onto t4r forums to post up to date documentation and photos of your traget...I mean misfortune.
*it would behoove you to carry these as barebone minimums
**paranoia
BONUS: if you want to shine above the rest, get a welder setup on your vehicle for those pesky repairs that normally would require a tow truck even with all of the above mentioned items. °Note: it is MANDATORY that you take photos for documentation of the cause, carnage, and repair welds and post them on this forum ASAP if using this method of repair on the trail.