I have been one of the lucky ones who have received an Arduino Mini UNO Gold Limited Edition .
It comes in a special case. It's a really small, black & gold and fully functional board.
As with the UNO the board comes ready to use just like the original Arduino UNO. Just change the USB connector, which in this case is a USB C and the Pin Header Pitch (distance between pin holes) is 0.05", or 1.27 mm. This is half the distance compared to the classic, regular sized UNO (0.1", 2.54mm).
After playing with it for a while, it has returned to the box, it will be a nice souvenir of this last year full of projects and surprise boxes from element14.
We'll think of a cool project for it.