Edit: it seems the Code field has a character limit (thanks to figlia for pointing that out below), here are both of them in complete form:
If you grabbed a free copy of Borderlands 2 from the Epic giveaways then these keys will give you some good gear for your character. Note that it requires a SHiFT account to redeem. Both codes are universal and should work on any platform.
I don’t have BL2 myself so I can’t say how likely you are to get something good. Please feel free to comment below if you have it.