Thank you! I spent a lot of time on polish, but most of it boils down to math. You can do the card-fan by setting card.angle = k*card.x to make it tilt, and then add a sprinkle of Math.sin(time + x) to make it bob softly. I use sin for a lot of animations.
The cards are randomly picked from a deck specific to each level, with some requirements like having at least 2 of each kind. Showing your deck sounds like a good idea, or perhaps giving the player a way to customize it. Currently each level more or less introduces a new card.