all my schit is always in my bag so i know where it is...
crescent wrench.
box wrench for my rear wheel.
set of cone wrenches (i need the 17mm to remove my front wheel, it's gummed up so i gotta hold the spacers in place when i loosen the track nuts).
ascent mini-tool.
chain breaker.
tire levers / pump / tubes / patches.

and i've been carrying spare keys in my kit for a while: spare u-lock keys, cable keys, house key, occasionally my car keys find their way in there.

plus... my bag always has a blinkie on it, and i keep my front light in my bag for when i'm riding in the boonies and it matters.