I use rentals for concrete work all the time, but I mean extracting boulders buried in fields, sticking up maybe a foot?
Yup, that is what I’m thinking of. 4 forks on a frame will have that out shortly. Nice thing is you don’t have to pay for a fancy purpose specific tool that can’t do much else. With 4 forks on, you can take a few bites of dirt out of the way as firm soil will stay on the forks long enough to pile it to one side.
The key to making pallet forks work for this kind of stuff, and to not kill the forks or the machine using them, is to use the forks as a 2nd class lever when initially popping the rock or concrete loose. That means getting the forks as far as possible under the object, then using a lift and dump action. It may take a few repetitions of that to get the stone or piece of concrete free of the soil, but it works. I use this technique extensively for taking out concrete flat work with my 1835s and I’ve seen good solid 6” concrete that was 6 or 8 feet wide break from the force, and not at an existing crack.