Basically their whole line of M14 parts would be fantastic. Lots of people here want Fulton and LRB parts to repair or rebuild Norinco receivers, but most ppl don't want to wait 2 months to get their parts. Especially if it's replacing a breakage.
As a minimum, you should stock bolts and all the bolt internals, gas pistons, bolt stops, all the roll pins, trigger and hammer pins, hammers, triggers, flash suppressors and sights.