Starter, Fossil, Eeveelution, Pseudo-L (Pseudo-Legendary), Legendary, Mythical, Baby, and Ultra Beast are all examples of Categories that can appear on these cards
This was a way for us to make cards like Astral Slide and Lightning Rift, but include a larger group of effects
Illustrated by Yeong-Hao Han Standard Not Legal Alchemy Not Legal Pioneer Not Legal Historic Legal Modern Legal Brawl Legal Legacy Legal Comp
Its a fantastic use of a meaningful bingo that directly synergizes with the cards effect
Theyre safe
It was never part of any official product line or promotional event allegedly printed as an internal test card, it accidentally received the Pre-Release stamp, which was typically reserved for early promo editions