This week's round of Golden Keys starts with 3 for Borderlands 3. There may be more released tomorrow, I'll update the post if any are or posted in the comments.
3 x golden keys for Borderlands 3:
dealbot has posted another 5 keys for Borderlands 2:
They're 'universal' so should work on any platform, but you don't need to own the game to redeem them. These are not codes to unlock the game, they're only for receiving special loot in-game. They can be redeemed in-game or through your SHiFT Account online (membership is free).