Mortuary + Phyrexian Altar + Bolas's Citadel + Bontu's Monument

Mortuary

Phyrexian Altar

Bolas's Citadel

Bontu's Monument

How it works

1. Activate Phyrexian Altar 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. Cast the creature from the top of your library by paying 1 life.
4. Bontu's Monument triggers, causing you to gain 1 life and each opponent to lose 1 life.
5. Repeat.

This clever loop turns the graveyard into your personal hand, letting you recast a cheap creature over and over to drain the table dry. By using Phyrexian Altar to sacrifice your creature for mana, you satisfy Mortuary's condition to instantly recycle that same card right back to the top of your library. From there, Bolas's Citadel allows you to play it directly from the top for a mere life payment rather than its mana cost, while Bontu's Monument steps in to make that cast completely free of color mana and cushions your life total with every cycle.