There are so many ways to do transfers onto polymer clay it’s hard to keep track of them all. Here a few you may have missed.
Tina Holden describes how to do transfers with Flecto Verathane
Valarie Aharoni has a couple types of transfers described on her blog. First she uses an
acrylic polymer medium on toner copies.
The second technique uses baking parchment run through an inkjet printer.
I also found JudiKins TranzIt Rinse-Away Paper. The instructions are at the Polymer Clay Review Blog.
GOLDEN (brand) Digital Grounds is a new line of products that are Ink-jet Receptive Coatings. They say you can do transfers on any surface with this product.
This one doesn’t say it’s for clay, but could be interesting if it works. Mist Hair Gel and an inkjet printer??