I hate multi-tools of the common types...they make a clumsy and inconvenient knife, have cast plier jaws that are basically fat needlenoses that are not good for gripping most fasteners, and some less used stuff that is also pretty clumsy. I use a German army pocketknife that has a decent selection of tools, a Springfield 1903 combination tool that is basically a nice range of screwdrivers that fold into the size of a nail clipper, and a couple of random nails and paper clips that are endlessly useful for improvised poking and stabbing.
There's a fierce little single AAA Maratac light and on my key ring nail clippers, a P-38, and a sliver gripper.
Good quality ignition pliers slide right in, real forged tiny pliers capable of gripping up to 9/16 and handling any amount of torque my hand can deliver on them. Beyond that, I think for an real wrenching you are getting beyond decent pocket stashing.
I have 4" adjustables that I don't carry, they have same range as the ignition pliers and less versatility, and anything above that range really should be in a tool box with a lot more.