I use the wild card for various things.
I might use it a the 'Old Maid' in Old Maid
I sometimes use it as a free chip placement in Bingo. If a student draws the wild card they can put a chip on any spot on their card.
It can be the 'zap' card if you want to play Zap
with the flashcards you already have.
If I'm playing Concentration
or Go Fish
, I put out two wild cards and make them worth double the points.
If I'm using the cards for discussion ot 'talking time', then the wild card actually serves as a wild card and I tell the students they can use any word they'd like, even something not from the set.