Veinwitch Coven + Dross Harvester + Phyrexian Altar

Veinwitch Coven

Dross Harvester

Phyrexian Altar

How it works

1. Activate Phyrexian Altar by sacrificing the one-drop creature, adding .
2. When that creature dies, it and Dross Harvester trigger.
3. Resolve the creature's ability, creating a creature token.
4. Resolve the Dross Harvester ability, gaining at least 1 life.
5. When you gain life, Veinwitch Coven triggers, causing you to pay to return the one-drop creature from your graveyard to your hand.
6. Activate Phyrexian Altar by sacrificing the token creature, adding one colored mana.
7. Cast the creature by paying one mana.
8. Repeat.