I've sold stacks of over 40 Gamma cores (At Tri-Tachyon that is 30,000 credits a piece for some decent cash...salvaging does pay quite well), but I kind of like the drop rate for Alpha cores, as it allowed me to nearly, but not completely maximize the output of my 3 colonies after exploring the entire map (albeit not super-thoroughly).
I think though that drop rates for Nanoforges/Synchrotrons is too high considering how valuable they are; every game I've had since 0.9a was released eventually led me to having many spares of these in storage. Since I ended up with spares, Corrupted Nanoforges are pretty much purposeless since I have more than enough pristine Nanoforges for my Orbital works.
I would actually like to see Pristine Nanoforges/Synchrotrons spawn only a single version in each game (A guaranteed spawn, but only one of each). Perhaps they could eventually be hidden behind a rather difficult task, but the eventual reward from obtaining one of these would feel a lot better IMO once you obtained them. Would also give a bit more significance to raiding Sindria if you really were planning on cornering the fuel market.