Earlier today, GoNintendo announced that there will be a Collector's Edition for the game which includes the following extras:
- An Agnès Figurine
- A Deluxe Artbook
- 34 AR Cards
- An OST CD
Besides those extras, GAME.co.uk will offer another artbook (smaller than the deluxe one), to all pre-orders of the game, be it the Collector's Edition or the normal game.
Source
Link to ongoing discussion