Fauna Shaman

The repeatable tutor that turns surplus creatures into the exact one you need. The activation is the whole engine: discard a creature, fetch any creature from the deck, and reset the loop every turn for a single green mana. The trade looks even on paper (one card for one card) but it is not, because the discard is a feature rather than a cost. It seeds a graveyard for reanimation, it lets a deck run a single copy of a silver-bullet creature and find it on demand instead of drawing toward it, and it smooths out clumps of redundant creatures into whatever the board state actually wants. The real checks live in the body, not the mana. The ability taps the Shaman, so each activation is one fetch per turn rather than a burst, and the 2/2 has to survive a full turn cycle before it does anything at all. That summoning-sickness window is the true vulnerability: an opponent who untaps into removal gets the card for free before it ever fires. What it does not give back is timing as a weakness, since with green mana available the ability can fire at instant speed (on an opponent's end step, or in response to a removal spell trying to strand a creature card in hand). Where Survival of the Fittest priced this effect at three mana and no body, attaching it to a creature made it both a clock and a value piece, which is why it has anchored toolbox creature decks wherever the creature pool runs deep enough to dig through.