These are fabulous! Little crochet key covers or key cozys, they are by Italian blogger Airali Handmade, she says they are made for a magazine - I'm hoping she has the pattern available in her shop soon too as they are absolutely brilliant and would make amazing gifts or little crafts to sell at a fair.
I had a google to see if I could find any more key cozies -
Key covers - "Cozy Keys" little knitted jumpers for your keys!
This bobble stitch knitted key cover protects your coat pocket linings and handbag lining (I lost £50 out of my pocket once - no lie, because of a hole caused by my keys!)
Koala Key Cozy - cute little koala bear and other little animals available with this pattern