I got a beast patch plus the vipor and both their player cards and double xp I have activated 7 codes already but I am hoping that there is at least 1 more patch and player card, at least a cool Monster logo one instead of more double xp that I can't even see how much time I have left on.
So I think the only duplicates you will see is double xp
As far as I know since there isn't a list of them, but like I said I have only used 7 codes so I have 3 more to find out. Unless someone can find a complete list somewhere.
Ah well if that's it then I got everything. I am kinda disappointed there isn't a cool Monster logo one. I also think they are giving away the viper one anyway so really the only one that is exclusive is the Beast.