Mortuary + Bontu's Monument + Yahenni, Undying Partisan + Gwenom, Remorseless

Mortuary

Bontu's Monument

Yahenni, Undying Partisan

Gwenom, Remorseless

How it works

1. Activate Yahenni by sacrificing a creature with mana value 1 or less.
2. When the creature dies, Mortuary triggers, putting the creature from your graveyard onto the top of your library.
3. Resolve the Yahenni ability.
4. Cast the creature from the top of your library by paying 1 life.
5. Bontu's Monument triggers, causing you to gain 1 life and each opponent to lose 1 life.
6. Repeat.

This loop turns the graveyard into your personal deck-builder by combining Mortuary with Gwenom, Remorseless, which lets you cast creatures directly from the top of your library by paying life instead of mana. To make this self-sustaining, Yahenni, Undying Partisan acts as the sacrifice outlet that feeds the creature back into the graveyard, while Bontu's Monument lowers the casting cost of your black creatures and turns the whole sequence into a lethal life-drain loop.