Is there a free ultimate game card code generator

No, there isn't. This is strictly because the actual Ultimate Game Card needs to be activated by the clerk at the store in which it is bought. If it isn't activated, it will not work, therefore codes given by a generator would be inactive, unless someone has just bought a card with that code and it was activated but not redeemed. This, however is extremely unlikely, seemingly impossible.

This is also fraud, since UGC's are bought with REAL money, finding a way to get them for free without explicit consent from the UGC company would be a felony offense. However there are certain websites that offer alternative methods of payment.

Also users who post their referral links here can expect to be reported to P2S.