Enduring Renewal + Workhorse + Loading Zone

Enduring Renewal

Workhorse

Loading Zone

How it works

1. Cast Workhorse by paying 6, causing it to enter the battlefield with eight +1/+1 counters on it due to Loading Zone.
2. Activate Workhorse by removing a +1/+1 counter from it, adding C.
3. Repeat step 2 until Workhorse has no +1/+1 counters on it.
4. Workhorse dies as a state-based action due to having 0 toughness, triggering Enduring Renewal, returning Workhorse from your graveyard to your hand.
5. Repeat.

This engine turns a mechanical clockwork beast into a perpetual mana machine by exploiting replacement effects and graveyard triggers. When you cast Workhorse, Loading Zone doubles its entry counters to eight, giving you plenty of fuel to work with. You then strip away those counters for colorless mana until Workhorse collapses under 0 toughness, sending it to the graveyard. At that exact moment, Enduring Renewal steps in to intercept the creature and bounce it right back to your hand, allowing you to recast it and repeat the cycle indefinitely.