I started building different attachments that would work from my trailer hitch reciever tube. It works like a 140 Farmall "quick hitch" that is a 1 prong fast change type reciever only my reciever is a 2" I.D. trailer reciever. When I want a new tool I get a piece of 2" tubing, slide it in and build off of that. I don't have to build the 3point hook-up each time, the reciever hitch is already built. And it make it easy to change by pulling 1 pin and sliding a new one in.
For a middle buster to lay off rows, I used a "C" tine from a cultivator that had a hole in it to mount my plow. I can carry it with 2 fingers and change it out in 15 seconds. You can also mount a sweep on the same c-tine if you need that. You can also buy old mule drawn plows at an auction usually for 5-10 bucks, adapt the end where the mule was attached with a piece of tubing and take the handles off. Our smaller 20 hp tractors really don't produce enough power to tear up the old mule plows. They are lightweight but I use them with a YM2200 tractor, works great.
For a cultivator, I took all the steel from a mule drawn "spring harrow" that had c-tines and seperated the steel into 2 sides. I mounted each side on a piece of 2 inch tubing that was dropped about 9 inches so the reciever hitch would travel over the plants but allow the rakes to run along side of the plants. It works great. I made each side to slide in or out to be adjusted to how wide my plants were.
I needed a rake to rake up old winter wheat after bush hogging so I took the hay rake teeth and bar they were bolted to out of a mule drawn hay rake, welded the tubing to it and in just an hour or so I had a hay rake on my Yanmar.
I built a 6' yard rake using hay rake teeth. I got my ideas off of this forum. I also built this to work from the reciever tube. It also does a good job. Beats the crap out of a hand rake.