I saw some Madoka Majica style Clow cards and thought that was awesome! I wanted to do pony versions for a while and have sketched out several, but I needed the template first. So here's my concept template for Pony cards inspired by (not direct copies of) the Clow.
Clow is from Cardcaptor Sakura for those who don't know. They look like this: [link]
EDIT: I already found some things I wanted to change... So I uploaded both versions in one. The one on the left (with the stars in the center) is the newer one, but let me know which you like better!
EDIT2: Forgot sourcing information:
paper texture - lostandtaken.com
Storm Cloud texture: