What's the rarest Nintendo game?

There are 15 rare Nintendo games and how much they are worth. There are 2 Nintendo World Championship. The Nintendo World Championship is called Grey Cartridge. There are four stadium events. The final conflict of 5 Hagane. The Nintendo campus challenge was held in 1992. There is a little man. Caltron 6-In-1 is one of the 8 Myriad 6-In-1s.