Sephara, Sky's Blade is a creature who is able to reliably cut her own mana cost down to a single white mana, by simply controlling a substantial number of creatures with flying
Loot, the Key to Everything Loot, the Key to Everything has a great, arching ceiling on its card draw ability
Ive already covered other stellar cards as footnotes in related entries, after all
Yawgmoth's Will lets you cast cards from your graveyard that turn, with the catch that anything heading back to the graveyard is exiled instead, but in fast formats that downside barely matters
Clive, Ifrit's Dominant Ben Starr's performance as Clive was one of the best parts of Final Fantasy XVI, and his MTG counterpart captures his essence well
Also, any non-Horror creatures with slime counters on them lose all of their abilities and have a base power and toughness of 2/2