Athreos, Shroud-Veiled + Enduring Bondwarden + Yahenni, Undying Partisan

Prerequisites

• You control at least one other nontoken creature.
• Enduring Bondwarden has at least one coin counter on it.

Steps

1. 1Activate Yahenni by sacrificing Enduring Bondwarden.
2. 2When Enduring Bondwarden dies, it and Athreos' third ability trigger.
3. 3Resolve the Enduring Bondwarden trigger, putting all counters from it onto another nontoken creature you control.
4. 4Resolve the Athreos trigger, returning Enduring Bondwarden from your graveyard to the battlefield.
5. 5When Enduring Bondwarden enters the battlefield, its backup ability triggers, putting a +1/+1 counter on the creature who had a coin counter placed on it, and giving it the printed ability until end of turn.
6. 6Resolve the Yahenni ability from step 1.
7. 7Activate Yahenni by sacrificing the nontoken creature with a coin counter on it, adding one mana of any color.
8. 8When the creature dies, its ability from Enduring Bondwarden and Athreos' third ability trigger.
9. 9Resolve the creature's trigger, putting all counters from it onto Enduring Bondwarden.
10. 10Resolve the Athreos trigger, returning the creature from your graveyard to the battlefield.
11. 11Repeat.

Effects

• Infinite +1/+1 counters on a creature
• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers
• Infinite death triggers