Mortuary + Phyrexian Altar + Aetherflux Reservoir + Bolas's Citadel

Mortuary

Phyrexian Altar

Aetherflux Reservoir

Bolas's Citadel

How it works

1. Activate Phyrexian Altar by sacrificing a creature.
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 X life, where X is the creature's mana value.
4. Aetherflux Reservoir triggers, causing you to gain 1 life for each spell you've cast this turn.
5. Repeat.

This loop creates a self-sustaining engine where Bolas's Citadel allows you to bypass mana costs and recast creatures directly from the top of your library by paying life instead. When you sacrifice that creature to Phyrexian Altar, you generate mana of any color while triggering Mortuary, which immediately recycles the creature back to the top of your library to be played again. Meanwhile, Aetherflux Reservoir turns your endless cycle of spellcasting into a mountain of lifegain that easily outpaces the life you spend, culminating in a massive 50-damage blast to eliminate your opponents.