The shower card can be found on p. 79 of the manual and was cut at 8" using 12 x 12 cardstock. It is a little large for me so I'm sure an 8 1/2" x 11" piece of cardstock and Fit To Page feature would be really nice.
I added a small sheet of white cardstock behind the card image to really make it pop.
Here it is.
*Wild Card Cricut Cartridge (p. 79) cut at 8"
*cardstock by Recollections
*Patterned paper by Colorbox