Enduring Renewal + Broodguard Elite + Workhorse + Phyrexian Altar

Enduring Renewal

Broodguard Elite

Workhorse

Phyrexian Altar

How it works

1. Cast Broodguard Elite for its warp cost by paying 1.
2. Activate Phyrexian Altar by sacrificing Broodguard Elite, adding .
3. When Broodguard Elite dies, it and Enduring Renewal trigger.
4. Resolve the Broodguard Elite trigger, putting a +1/+1 counter on Workhorse.
5. Resolve the Enduring Renewal trigger, returning Broodguard Elite from your graveyard to your hand.
6. Activate Workhorse by removing a +1/+1 counter from it, adding C.
7. Repeat.