Here are a few from S. Korean casinos.
These cards can be used in lieu of a passport so it is closely guarded.
I've never found one laying around in a slot machine.

This Seven Luck casino card has four languages on the back. It has Korean, English, Japanese & Chinese.

This newer Seven Luck card has a QR Code on the front. QR Code was first developed in Japan for the auto industry.
It's in widespread use in S. Korea.

This Seven Luck card is a higher level card and has English & Japanese on the back. The name on the front is Japanese (blurred).
Robert Reno sent me this. Thanks Robert!

This is a Golden Gate casino card. The casino is ten minutes away by a free shuttle bus from Incheon International Airport.

This is a card from the only casino that allows S. Korean citizens to gamble, Kangwon Land Casino.
I might be shot for being a spy if the Korean government found this in my possession.