I have a 2dr and carry a decent amount of stuff now as it is. Trying to slowly add too it as I see fit.
Tools: I carry a set of wrenches (standard and metric) crescent wrench, pliers, dikes, wire stripers, a set of metric and standard sockets, ratchet, extensions, needle nose pliers, vice grips, test light, a couple different sizes of screw drivers, pry bar, hack saw, hammer and a BFH lol. Hopefully will be adding some air tools too since I have a Kilby OBA.
Parts/vehicle supplies: In one plastic organizer thing I have fuses, air fittings, some wire, and zip ties. I also carry spare air line in both 3/8" and 1/4". Motor oil, water (can be used as either drinking water or in radiator if necessary), Some assorted nuts bolts and washers of various sizes and lengths (Cant carry every size but having a few has saved my ass on more than one occasion), funnel, brake clean, WD40.
Survival Gear and Outdoor Gear: Usually just have this in a backpack that I put in the Jeep when I wheel. Large fixed blade knife, compass, maps, magnesium bar, can opener, rain jacket, wool socks, beanie, first aid kit (also keep one in the back of the Jeep), flash light, survival kit (also keep one of these in the Jeep at all times as well as another knife) these have things such as matches, tinder, fishing line hooks and weights, tin foil, compass, signal mirror, a few quarters (in case you need to use a pay phone or something), clothes pins, etc etc. I carry a full water bottle in the back pack, gloves, water purifier, and some other small misc stuff. Soon going to add some climbing/repelling gear. I also usually throw a small axe in the back of the Jeep as well as my binoculars. I also have an MRE and some extra water I'll throw in if I know we're going on a long trip. Always keep a pair of boots and socks in my Jeep as well as a Jacket. Also keep a pair of hand held 2-way radios in my back pack.
Misc Gear: Large zip ties, duct tape, bailing wire, electrical tape, epoxy (for metal and plastic), hose clamps.
Recovery Gear: Tow strap, tree strap, about 4 shackles, snatch block, short 5/16" chain, gloves, winch line dampener, army shovel. Would like to add a High Lift Jack and some of the accessories for that.
You'd be amazed how much shit you can cram into a 2dr and still have the back seat open LOL. I'm sure theres stuff I usually have in my Jeep that I'm not thinking of. And there's still more stuff I would like to add. Theres a good thread about this somewhere. Let me see if I can find it.
EDIT: Here's that thread https://www.jkowners.com/forum/showthread.php?t=12831
I should also mention, that its a great idea to carry things that you can use for multiple purposes. Heres a few examples bailing wire can be used to reattach something if necessary, secure a tarp, wire something back together; air line of course can be used to repair air line, can be used to fix a fuel line with wire or a couple hose clamps to get you off the trail, can be used to syphon fuel if necessary; duct tape has limitless uses. For survival gear the same thing goes, tin foil can be made into a cup to boil water, is reflective and can be used for signaling and such as well as temporary water storage. Point is using things that can be used for multiple things means you can use it for multiple resources if you absolutely need to and it can help cut down on some weight.