It's far easier to have AI alter existing photos to a style you want. I'm just having it alter them to plain 'animation.' It's really great, but will take an extra step for old-timey players, where all of their photos are b&w.
Here's some Barry examples:

In the games I'm learning about and drawing inspiration from here, players take turns pulling up characters and actions and supports and and and, then the other player does the same, then the first player can attack with them on his next turn, while his opponent does his best to tank it or avoid it. They go back and forth until someone is defeated and the other wins.
With football, I'm thinking the first player sets up his blockers by laying them down, then the opponent lays down his defensive line, maybe front 7 (not 7 players, but that's the idea), back to the first player then laying out all of his skill position player cards (1 RB? 3 WRs? 2 TEs? etc). The defense then sees the formation/possible play call based on it, and lays down his DBs. The play begins, and given enough blocking, it can be a successful play. The opponent on defense is trying to combat the play call and obviously defend to prevent a first down.
I'm thinking something like 5 consecutive first downs by player 1 = a TD, maybe only 4 = a FG, and if stopped at 3 or fewer, it's a change of downs. Can't get too deep with the football (ie-special teams) or it won't play at all like these card games do.
It's the battle dynamic of them with some football aspects included and as the theme.
The thing about these games is there are a LOT of card variety. The Magic the Gathering one is like 30 years old, but they're still coming out with new decks and in those 30 years, they've produced over 20,000 uniquely different cards. That's nuts.