An anniversary set with only special cards
We'd sooner label nothing than label it wrong
Even better, it asks you to sacrifice the creatures you put counters on, which opens you up to lots of nonsense with The Ozolith
Running a blue-black dual land that can also be used to cast either Force of Negation or Grief (both Modern staples) for free could just be an appealing enough proposition on its own in the right deck
Xavier Kerr [CA] (8/3/3), Charizard ex/Noctowl 141
Each card in the deck must differ from each other card in the deck in at least one of the following: Name, Pokmon Type, HP, Retreat Cost, Weakness, Resistance, Ancient Trait, Ability, Pokmon Power, Pok-Power, Pok-Body, or Attack (where attack cost and base attack damage are considered a part of the attack), with the following exceptions: You may include any number of basic energy cards with the same name