Congratulations on the new Kubota. That puny toolbox that came on my Kubota was too tiny for me. I mounted a larger tool box on my L2501. Big enough to hold a half roll of paper towels for sweat/grease on me. A hammer/chainsaw file/small pipe wrench for turning the screw adjusting thing on the right side arm. Lots of extra pins as you mentioned.
I have a large crescent wrench hanging on the hook for my top link for 3 pt. adjustments and a couple of 6" in my tool box along with zip ties, small vice grips, shear pins, screw driver, electrical tape, just about anything I might need for small field repairs. Luckily I am usually within 1/4 mile of my shop if something does happen. But since the shop is at the highest point on my property it is always an uphill walk.
Couple of big crescent wrenches for the three point hitch adjustment, extra lynch pins, large rubber mallet to help get the lift arms on and off of implements, and a couple of lengths of 3/8th chain for lifting stuff with the FEL. Might be a few other odds and ends but I can't think of what they are right now.
Both my tool boxes have extra hitch pins, a pair of slip joint pliers, a West Virginia socket set (Crescent wrench), straight blade screwdriver and a No. 2 Phillips...and a box cutter with a spare blade in the handle. Also, a pair of gloves (usually greasy) from the PTO shaft hooking up and unhooking implements.
In the cab I keep my cell phone and we have business band 2 way radio's plus a short barreled rifle behind the seat.
Crescent wrench, channel locks, multi tip screw driver, a piece of conduit to fit the pins that stick out on my top link and a greasy rag. I also keep a very small crescent wrench and channel locks in my pockets all the time. The little channel locks make it easier to pull the pins in my front end loader stand when my hands are hurting. Ed
There's was also that unknown object that was in the box when I bought the used tractor from a dealer. The box was cleaned out except for that object and the cat. 2 hitch balls. I had the feeling the origonal owner thought I'd eventually need it. Well the engine is now running rough and I probably need it. Wonder where it goes???
Let's see. Channel locks, hammer, crescent wrench, gloves, and a allinone screwdriver plus the top hook for the quick hitch, extra pins and bushings in the big one.
Chainsaw "stuff" in the original one. I moved it to the floorboard under the loader joystick and put a larger one on the back.
The normal spare pins, a rag, fence pliers, wire cutters, chainsaw tool, chainsaw file, chainsaw wedge, 25' and 100' tape measures, water bottle, couple wrenches, few Electric fence insulators. Probably some other junk in there I can't remember.