I carry my mobile charger, a quality extension cord (you might be able to plug into a socket outside of a hotel or home, etc it's not much but it can easily cover sentry mode losses), I got the tesla pump and fix a flat as a present so I have that, and lift pucks (https://www.amazon.com/KOROP-AUTO-PARTS-Lifting-Compatible/dp/B091FGGR11) just in case I need a mechanic that has never taken care of a tesla before.
In the cabin, long usb C cables (ours to lightning), rain ponchos (leftover from maid of the mist), and if its a really long trip- https://www.amazon.com/gp/product/B07YH9XPXR - back seat organizer and tray... for that fast food stop the kids get a table.
I can also say - depending on the trip, I've carried these so we can sit outside: https://www.amazon.com/gp/product/B08697LCY4 crazy sturdy.