Let's see...depending if you have a 4WD and do a lot of off-roading...maybe front suspension and steering parts, timing belt, water pump, tires, belts, hoses, fluids (brake, engine oil, coolant, power steering), filters, ATF (if you have an automatic transmission), sway bar bushings, end links...these are just a few that I can think of right off the bat.

1998 T-100 Xtra cab SR5 2WD Auto; Roadmaster Active Suspension; Yokohama Geolander HT-S; lowered air dam; full belly pan; 4? diffuser; 11" side skirts; dual transmission coolers; 67% grill blocked; Auto-RX'd; ScanGauge II/Ultra-Gauge