I just discovered Artist Trading Cards and they are cool!
Artist Trading Cards (or ATCs) are miniature works of art about the same size as modern baseball cards or 2 ½ X 3 ½ inches (6cm X 9cm), small enough to fit inside standard card-collector pockets, sleeves or sheets.The cards are usually traded or exchanged rather than sold.
Here are a couple that I experimented with...
Drop me a comment if you have tried them also. I would love to see them!