I've been very careful to get my on board tool kit down to a minimum, But I'm planning a trip for next summer that will be long enough that an oil change will need to be done along the way. I'll want to carry a few extra tools along for that and other things. I already had an old tool box from a Honda ATC90 in my plunder, so I decided to put it to use. 99% of the time it will be empty, but when I need it I'll be happy it's there.
I'm not an aggressive rider and almost all of my riding in on dirt and gravel roads, or abandoned roads and logging trails. Not a lot of real off road riding is available here. The pictures make it look larger than it really is, it's only 6" long and 2 1/4 in diameter. I'm not concerned with any clearance problems, it's 11" above the ground and if it does get bashed, I've got another one
I carry a shortened 3/8 drive ratchet, two 2" extensions, 8mm, 10mm, 12mm sockets in the front tool carrier. To the stock tool kit I've added a 5mm allen wrench, and a 19mm box end, I replaced the stock pliers with needle nose vice grips. I know the factory screw driver is cheesy but I left it in just in case, I've changed all the phillips head screws to allen head or 8mm head so I should never need the screwdriver.
I added the 19mm for the axles, you need a 19 and a 22mm for the rear, the factory kit has a 19 and 22mm but they are on the same wrench, kinda makes it hard to hold both sides. And for the front you need two 19mm's.