Veinwitch Coven, Daxos, Blessed by the Sun, and Phyrexian Altar

Prerequisites

• Veinwitch Coven on the battlefield
• Daxos, Blessed by the Sun on the battlefield
• Phyrexian Altar on the battlefield

Steps

1. Activate Phyrexian Altar by sacrificing the one-drop creature, adding
2. When that creature dies, it and Daxos trigger
3. Resolve the creature's ability, creating a creature token
4. When the token enters, Daxos triggers, causing you to gain 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. Resolve the Daxos trigger from step 2, causing you to gain 1 life
7. When you gain life, Veinwitch Coven triggers; decline to use its ability unless you have excess mana to spend
8. Activate Phyrexian Altar by sacrificing the token creature, adding one colored mana
9. Cast the creature by paying one mana
10. When the creature enters, Daxos triggers, causing you to gain 1 life
11. When you gain life, Veinwitch Coven triggers; decline to use its ability unless you have excess mana to spend
12. Repeat

Results

• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers
• Infinite death triggers
• Infinite lifegain