Remember the flywheel tool. Also a cheap 19volt impact is nice to remove that sucker quickly. What you bring is also dependent on your riding area. Hard terrain, mud, sand, they all would have a tendency to loose/break different parts.
I ride 100% sand, so extra bars are not required (soft rollovers typically). I always have different main jets, second sprocket, second chain, extra clutch, brake, and shift levers. Extra clutch and throttle cables could be useful. I have a full set of spare electronics too.