I have a Rigid tool box that rides between the back seat and the door. It is a very tight fit. As in, it needs to be in the right spot so that it will fit, tight, and I doubt it will come out in the event of some stupid jeep trick. I have a tool roll, a socket set, in its original container, recovery gear in its bag, an electric impact wrench, and a full set of impact sockets in the box. I also have a first aid kit outside of the box, and a tow strap that may make it there, some day. I haven't needed to open it yet, so I will see where it ends up after it is opened.
I have my HiLift jack mounted high on on the roll bar behind the back seat with Muffler clamps. IT took a little positioning to get it where someone wouldn't bump there head. I have sons that are 6'4", and when they are punished by sitting in the back seat because my wife is coming, they haven't complained. I don't know if smelling salts to get them out of the back seat had something to do with that... (I kid, they really don't bump their head.)
Zombie apocalypse rations are stored in the recessed compartment in the back, along with some water, and a foldable shovel. Without looking, I think that is all I have in there. I am at work and drove my truck in today. It is outfitted fairly well, too.