One of my best sellers is the fridge magnets with my various fantasy art designs on them, I try and do about 3 - 4 new designs in a week if I can.
Here's my best seller at the moment.
Dark Death Reaper
Also there are other sought after gift ideas that are really in demand with collectors, so it's well worth creating an account with cafepress, so as to get your designs out there, of course there are other ways of promoting your art online and you shouldn't stick to one method alone.
Buttons or Badges - With Unique Designs
Dark Death Reaper Button Design
Dark Death Reaper Sticker Design