Sounds like you are taking the essentials - I'd add Duct tape, zip ties, WD40. These will mend absolutely everything, apparently...!!
Seriously - I have a basic tool set with torx bolts, plus - hi-vis vests, first-aid kit, oil, coolant, tyre inflator, tyre weld, towing rope, zip ties, WD40, duct tape, fire extinguisher - in the back of mine. Overkill for sure, but might help with any small issues...
Also, breakdown cover - just in case of something serious...!