The arts in this mod are very well-made, though I want to discuss some of the difference between the base game and the mod. Maybe it can help you creating those unfinish art.
In the base game, most of the time Attack card has red background, Skill card has blue background, some of the Skill card that mostly do attack thing also have red background, and power card... power card gets whatever color they want.
This way all cards have a consistent art style, and player can easily tell what those cards are.