Confirmed that these are uncontrolled/unregulated aftermarket items. There was a period of time several years back where it seems someone or multiple people were stamping cards with fancy images (Special Olympics was one I recall seeing a lot) and 1/1 notations. They make fun variations to chase. They are worth what you are willing to spend, but given there is no control over the manufacturing of them, what is to stop the person from making more than 1 or even more likely, just stamp 1000s of random cards and sell them for a premium? Nothing, which is why they should only sell for a very slight premium about the base card or same amount. Some might even say less, since they are now defaced cards. Depends on your opinion. Worst case, its a sort of "custom".
It's called copyright infringement. Upper Deck released it as a stand alone product. Someone other than UD added the diamond addition logo. If UD wanted to do something about it. They would have. People might not realize that. And pay extra money to buy them.