Collect the indicated number of stamps to unlock the corresponding board.

Board	How to unlock
Cardboard	224 stamps (8 boards complete)
Cheese	56 stamps (2 boards complete)
Deco	168 stamps (6 boards complete)
Future	6 stamps (6 properties owned)
Ice	112 stamps (4 boards complete)
Jungle	84 stamps (3 boards complete)
Sweet	22 stamps (22 properties owned)