I bought a cheap china made set of 3/4 drive sockets about 25 years ago that have helped me a lot on really tough stuff on my tractors. Last recourse before breaking out the Blue Wrench.
I've broke a few sockets, the ratchet and breaker bar over the years but have replaced them with good used USA made ones off ebay as needed. Look on craigslist for a set.
You will need a decent set of combination wrenches. 15/16" is commonly used.
Also a pair of 1 1/8" combination wrenches if you ever need to split the tractor - both at the front and rear end of the engine.
You will use 3/8" drive ratchets more than anything but I like to use a 1/4" drive set for reinstalling the tin, etc in tight places. Also a 3/8" swivel/u-joint and 2", and 6" extensions if you ever need to remove your starter or injector pump.
Fleeler gauges. Brake tool is nice but you can do it with a big screwdriver too.
3000 is a great tractor. Absolutely bullet proof, good new and used parts availability, easy to work on, etc.
What options did you get - gas or diesel? live pto? tranny?, power steering? differential lock?
Here is my own little sweetheart 3000. Built from parts from at least a dozen different tractors.
Some day I'll get around to repainting it.