On the player status page, click on the promotions page. From there at the bottom, hit the enter code button. Unlock the following cards by entering the corresponding codes, one card per deck and up to a total of 40 cards for each deck:

CARD - PASSWORD
Promo Unlock 1 - WMKFGC
Promo Unlock 2 - KWPMZW
Promo Unlock 3 - FNMDGP
Promo Unlock 4 - MWTMJP
Promo Unlock 5 - FXGJDW
Promo Unlock 6 - GDZDJC
Promo Unlock 7 - HTRNPW
Promo Unlock 8 - NCTFJN
Promo Unlock 9 - PCNKGR
Promo Unlock 10 - GPCRSX