We've got Artist Trading Cards. Joumana Medlej, who wrote a primer on ATCs, says:
"As their name indicates, ATC are collectibles, a brilliant idea born of the older sports-themed trading cards. The one rule that makes an ATC derives from their origins: the dimensions of the ATC must be 2.5" x 3.5", or 64 x 89 mm."
You can use any media with ATCS, including beads, clay, and glass!
An important aspect of ATCs --
They are meant to be traded, not sold. Below the images, you can find links with info about making and trading them.
Jason and the Golden Fleece
by Liz Ness
By Ian Bertram
By Denise Smeaton
by Dana Lynn Driscoll
~ Go Make Something's ATC FAQs
~ Artist Trading Card swaps for students
~ You can find people to trade with at ATCs for All or Illustrated ATCs.
~ Here's an article with tips about hosting your own ATC exchange.