They popped up on my YouTube shorts feed a few weeks ago; as best as I can tell they’re a fan-made set of booster cards, with the purpose of parodying/piggybacking on the current booster cracking (gambling) craze - right down to the fact that it has its own set of rare ‘chase’ cards.

I just find the low-effort art style and names charming, without ever feeling the need to participate.