In December 2015 I made my youngest a playing card holder from thin card board and duct tape.

The concept is simple, a slot made from two folds of card board, the back fold slightly higher than the front, then a wide base so the cards stay steady. The duct tape holds it all together. I left the card board exposed where the cards are inserted, so the cards will slide in and out easily.

My youngest can use this to play Uno, even when the hand has nearly thirty cards. I am amazed that it is still working well ten years after I made it, and that it gets frequent use.