0) Jumper cables
1) large slotted screwdriver -sb long enough to jump the starter solenoid
2) large Philips screwdrivers,
4) large vise-grips
5) large crescent wrench
6) coat-hanger wire
7) Hose clamps of various sizes
8) zip-ties
9) Muffler Hangers
10) work gloves
11) I keep a leatherman with tool adapter and various added sockets and socket extenders and u-joints that work with the tool adapter so I don't carry seperate small screw-drivers or smaller pliers or wrenches. My auto-maintenance skills are none too advanced either.

Of course there must be a few other oddbits

gas can
radiator stop-leak
anti-freeze
fix-a-flat
Transmission sealant - don't use this stuff unless necessary it is a death warrant for your tranny but it may get you to your destination when nothing else will.

Transmission fluid
oil
Duct-tape
roll of electrical wire
spare fuses for every fuse in the vehicle
wiper blades
windshield washer fluid
Dry-gas
Starter fluid - ether
road flares
hazard flag
couple of hazard triangles
Improvements on mfg-supplied jack - I always carry an X wrench because the silly lug wrench provided is never useful if the lugs are properly tightened.
tow strap
tie-down straps
fire extinguisher
spring loaded center punch
flashlight
bungie cords


in winter I add
Shovel
Sand
Traction mats


The above only covers the vehicle I also carry basic bob type stuff as listed below

Space blankets 1 per seat in vehicle
emergency ponchos 1 per seat in vehicle
umbrella
Gallon of water
Rations
Candle - large, in tin with multiple wicks and sealing top. provides heat and light if car is stalled in winter storm.
In winter I add a CarHart coverall, insulated boots and wool socks and extra jacket for the driver - ME In fact I left those in the trunk this summer since I didn't need the space for anything else.

I also work as a volunteer EMT so there is always an EMT first-in bag in the back seat. Large list of contents there. Mostly airway management and bandaging.

I take a modular approach to the kit thing so since My EDC + PSK will be with me in the car I don't replicate them in the Vehicular kit.