Whats the best unit and setup to use to get good classic game synth sounds? I've tried some subtractor and NN19 mono's but cant seem to find the good ones.

check out youproduce.net -- it's an amazing site with TONS of refills -- mostly for sale (but not expensive at all) -- and usually there is a free demo -- i belive they have a refill of classic 8 bit sounds -- all arranged in nn-xts for you

also, check out 8bitpeoples.net if you are into chip music -- they don't have samples, and i do not in any way recommend you sample any of the work on their page -- it is free to listen to, download, and share, but not available for sampling -- it's a great place for inspiration! (check out firebrand boy -- AMAZING!)