Edit (to stay on topic): I would not personally consider this a cameo as it’s on the backside of the card and the box cover isn’t even the main focus there. Yes, Pikablu is there but at that point you’re better off just getting a copy of Pokemon Dash and grading the video game.
Since when would a non card art suplement count? It’s video game cover art, so unless you put the game box or cover paper in your binder, I can’t let you accept this proposition in good faith. For it to be a true cameo it has to be in some way a part of the actual card art in some way. This isn’t.
No need to thank me —- your wallet can. Just doing what I can.
First I voted for yes, because the simply thing that you have to ask this means that Marill is there.
But after that I thought that the Pokemon have to be at least visible… Without knowing the original artwork is it possibile to see a Marill or you can only see some blue dots?
So I voted for NO
These aren’t even really pokemon cards, but even going past that semantic like Brendan said it is not unique art, nor is it even part of the cards artwork
As a Clefairy collector I would not count something like this
My motto is “a piplup is a piplup, no matter how small,” so yes, that would be a cameo (piplup is included in one or more of those backs as well).
However, I’m also of the opinion that those were never “officially” released, so I’m ignoring them for now for my own sanity. I consider the Creature deck cards to be in the same vein as the mini gacha cards or similar TCG-offshoot, since they aren’t tournament legal and they weren’t mass distributed.