Thaumaturgy Core

Whenever you sacrifice an artifact, draw a card.
{x}{u}{t}: Return target artifact card with mana
value of {x} or less from your graveyard to your
hand.
{t}, Sacrifice Thaumaturgy Core: Create 2 Thaumaturge tokens. (It's an artifact with {2}, Sacrifice this artifact: Draw 2 cards or gain
4 life.)