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There's a lot of things that are obvious like screwdrivers, zip ties, etc. Some things a little more unique:

I prefer to carry a set of flex head ratchet wrenches and a crescent. The crescent generally covers for a full set of combo wrenches, and then the ratchet wrenches generally replace a ratchet and sockets. There's some cases like lug nuts or something which you can't use a ratchet wrench for, but more repairs they can tackle the task.

I also carry a small multimeter, or even better if $$ isn't a concern a Power Probe will help you test and diagnose anything electrical. Then a jumper wire with an auto fuse holder in it.

A really good set of pliers which for me is a pair of Knipex Cobra pliers.

Sheet metal shears, they're not too big and they can cut just about anything from wire, plastic, metal, etc.