Ball joints, tie rod ends, ujoints, serpentine belt, idler pulleys, O2 sensors, all fluids in the vehicle, bushings at track bar/shocks/etc., shocks, all consumables you can think of.
This is what I found on my '99 I bought at 150k. I wouldn't hesitate to buy another higher mileage TJ as long as it was in good mechanical shape at the engine, transmission, transfer case, and axles. I'm about to trade mine in on another Jeep and the above list will be exactly what I o through when I get it home. It has 50k on the clock though so I don't expect as much stuff.