This can turn your moderately concerning battlefield into something thats immediately terrifying for your opponents to deal with
A players team cannot contain two Pokmon of the same species, that is, with the same National Pokdex number (for example, Heat Rotom and Wash Rotom are not allowed, since both are still Rotom)
Most of these cards are great, though some are a bit overcosted even if they stick to the theme, like Eater of Hope
In Midnight Hunt , Wizards gave us two such mechanics: Daybound/Nightbound and Disturb
For example, if I'm building an aggressive Black-Red Vampire deck that wants one-drops, I'm definitely including four copies of this card: Once again, the power of a 2/1 diminishes quickly as the game goes on
I love this about card moves