Just a small square with a note on one side and a picture on the other.
I drew most of those (and traced the rest).
It was pretty cool and most really liked them.
I had one kid who asked me to draw him Poseidon.
When I gave it to him
He was so pumped up
"ITS POSEIDON!! YEAH!!!"
"SO COOL!"
And it just made the 10+ hours of working on those cards more than worth it.