To unlock more teams got to the Settings/SecretCodes and type

 GOLDENGOD     All Classic Teams
 LACESOUT      All Rams Team
 NEVERMORE     All Ravens Team
 WILDCARD      '72 Raiders
 PICKEDOFF     '77 Cowboys
 GORMENGHAST   Monster Team
 HYSTERIA      Sugar Buzz Team
 ROCKTHECASBAH Mummy Team
 IFOUGHTTHELAW Marshal Team