Nicola posted one a little while ago – that listing ended at over $1,500 back in April. The first listing offered a detailed description which was copied by the current auction on eBay:
Prior to a Hu-Card being produced, TG-16 games were released on very limited run PC cards for internal testing. This plugs into the game slot of a TG-16 and runs just fine. This card came directly from NEC America in 1989 and I can vouch for that. Look up info on TurboPlay magazine, I was the Publisher and worked with NEC and Hudsonsoft.  Not only is this a rare item but it contains one of the most beloved TG-16 games ever produced.  I also published VideoGames & Computer Entertainment magazine and we used this card to run a cover story on Military Madness that is still referenced even today!  This particular card was a loaner from NEC and we were supposed to return it after 14 days.  NEC knew I was passionate about the game and they let me keep it – if not it would have been destroyed long ago and not be here today.
Less than 3 days to go. There is a reserve on the auction but its currently sitting at over $500