This is a total collectard post, but after 6 years of searching I finally completed the NTSC Sega Master System re-release variants set, all complete in box with manual. I now have everything released in North America, ever, including variants (except for a UPC sticker Sonic, which is easily duped and I refuse to pay $1200+ for).

Rambo and Choplifter hadn't shown up on eBay in years (except for one Rambo auction that ended north of $200). Some guy posted both on the same 3 day auction and was able to nab them finally.
If anyone's unfamiliar, these are games that Sega re-released (mostly as blue label carts instead of red label, but all with different packaging) for the SMS shortly before the Genesis came out. They were printed in extremely small quantities with some being rarer than others (Rambo is the hardest to come by).
I'm done being a collectard now. Complete set collecting is for the birds.