For planter, shop hammer, large flathead screwdriver, normal size Phillips, 3/4 pull handle with 24mm and 30mm, 1/2 ratchet with 18mm and 24mm, 2 each of 10, 13, 15, 16, 17, 18, 19, and 24mm wrenches, 3/4, 7/8, 1" wrenches, and adjustable wrench.  Usually service truck is close if it's major but most common issues I can fix wherever I am in the field without driving out to the truck.  Also keep hydraulic o-ring kit, marker bearings, seed hose ends and o-rings, seed tubes with sensors, spare row clutches, marker shear bolts, contact cleaner, shop rags, pneumatic couplers and tee fittings, telephone splice connectors, and electrical tape in the cab along with 5 gallons of hydraulic oil, spare gauge wheels and closing wheels on the planter between the tanks.  It's not uncommon to be a few miles from the truck and tender and by myself from the time I leave the shop till I get back after dark.  So anything that can save downtime and keep the planter moving is worth it.  Cab is really pretty neat with all the room behind the seat for storage along with the armrest, and storage behind the buddy seat.  No one can accuse me of not having enough tools, or at least making a good attempt.