Although most seem to be against card effects for kid's shows for obvious reasons, I think this one would play well.



"A totally captivating magical comedy routine that's enjoyed by children and adults alike! Great for stage work, but can also be performed in close quarters, and surrounded.

Let a spectator choose a card from the deck by removing it, looking at it, and replacing it into the deck. Introduce the magical card duck, who has special powers- the duck can instantly find the chosen card, even though it is buried in the deck. Place the deck in the card holder in front of the duck, and suddenly the duck springs forward, puts his beak on the deck, and springs back with the selected card firmly gripped in her bill. This is a time tested favorite that gets a great reaction every time!"

wow! that looks really cool, where can i find that?

magictricks.com

Or ebay

too expensive.

I remember this effect from when I was a kid, so you know it is old. But nonetheless a very good effect, this would play well with most kids, especially younger ones. You have to ensure that they know all the cards are different (for younger kids) as some don't grasp the whole suit/value thing.

I know a guy that has been performing this duck for about 25 years. It has been a major part of his act, it's half trick, half vent act. The duck keeps getting the card wrong and there is a bunch of comedy he does with that. The duck ends up laying an egg in the end (literaly) and it's their selected card. Pretty funny really.

By the way, he uses alphabet cards. It works better for him and allows for a lot more patter and funny bits.