Leveler + Out of the Tombs + Gate to the Afterlife + Phyrexian Altar

Leveler

Out of the Tombs

Gate to the Afterlife

Phyrexian Altar

How it works

1. Cast Leveler by paying 5.
2. Leveler enters the battlefield, exiling your library.
3. Activate Phyrexian Altar by sacrificing any creature, adding one mana of any color.
4. When the creature dies, Gate to the Afterlife triggers, causing you to return any creature from your graveyard to the battlefield due to Out of the Tombs, discard a card and gain 1 life.
5. Repeat from step 3.

This loop turns an empty library into an absolute engine of creation, starting the moment Leveler enters the battlefield to instantly exile your entire library. With your deck reduced to nothing, Out of the Tombs steps in to alter your draw step: whenever you would draw a card, it instead resurrects a creature directly from your graveyard to the battlefield. You then feed that creature to Phyrexian Altar to generate infinite colored mana, which in turn triggers Gate to the Afterlife to gain life, loot cards away, and keep the graveyard fueled.