Now, imagine double panel cards with two feral-hybrid panels on them. Fire-Water on one half, say, and Earth-Air on the other half (five of these possibilities, for each halfsies combination (vertical vs horizontal) for a total of ten possible cards. Or, since we're making up a totally new kind of card here anyway, do like I've always wanted to try and make them diagonal split. Oops, there's still ten then, since you have to make the diagonals go both ways, for balance.
I like it. It's intriguing. I'm tempted to doodle up some art and make some stickers and sacrifice a deck.