Students from Class Zero are in the collectable card game and some even have two cards. Ace and King are fire characters while Deuce and the Type-0 Moogle are water. Machina and Queen are ice. Trey and Seven are wind. Cinque and Eight are earth. Sice and Nine are lightning.
Square Enix also included characters from Final Fantasy XII, Final Fantasy IX, the Manikins from Dissidia 012[duodecim]: Final Fantasy, Crisis Core, and Dirge of Cerberus characters into the mix.
Famitsu has pictures of the complete Chapter IV set here.