2 Hammer of Purphoros Although Hammer of Purphoros is technically not a creature, its often one of the most unique cards in many matchups
Its a reset button that leaves almost nothing standing, making it a powerful closer for black decks that excels in long, grindy games
Snapcaster Mage Snapcaster Mage went from the best blue creature ever and a blue staple across multiple formats to a barely playable card
It will also retain its name, colors, and supertypes, but it will be an Aura enchantment with no other types or subtypes
Being able to deal with Tarmogoyf for one mana (the previous best answer was Liliana of the Veils second ability or a Ulcerate) was a revolution for the modern format
Once you're satisfied with your crop of the dead, swing open the doors and unleash your unstoppable Zombie army