I'd take a gallon of oil.
An extra fuel filter if you have a deisel. Had to change a couple of those because of bad fuel.
Extra headlight. Truck stops always charge premium.
Fuses and bulbs
If you have air breaks its always wise to have some way to splice air-lines so you can get it to the shop. They dont call that big chunk of tread in the middle the road a gator for nothing.
It'll reach up and bite ya.