The pre-order bonus for Kingdom Hearts 3D [Dream Drop Distance] for 3DS will be a set of three AR cards.
From Square Enix
Using these cards will allow players to unlock rare Dream Eaters and a 360° viewing stand that allows players to take a closer look at their Dream Eaters from all angles.
One wild AR card will randomly unlock one of the three rare Dream Eaters: Ursa Circus, Sudo Neku or Meowjesty. The second AR card unlocks R&R Seal Dream Eater, and the last AR card unlocks the 360° viewing stand.