Mortuary + Ashnod's Altar + Bolas's Citadel + Willow Geist

Mortuary

Ashnod's Altar

Bolas's Citadel

Willow Geist

How it works

1. Activate Ashnod's Altar by sacrificing Willow Geist.
2. When Willow Geist dies, it and Mortuary triggers.
3. Resolve the Mortuary trigger, putting Willow Geist from your graveyard onto the top of your library.
4. Resolve the Willow Geist trigger, causing you to gain 1 life.
5. Cast Willow Geist from the top of your library by paying 1 life due to Bolas's Citadel.
6. Repeat.

This loop sets up an ingenious self-sustaining engine right off the top of your library. Ashnod's Altar acts as our fuel source, converting sacrifices into colorless mana, while Mortuary catches our fallen creatures and neatly tucks them back onto the library. Bolas's Citadel allows us to bypass traditional mana costs entirely, letting us replay those top-decked threats by trading life instead of mana. Finally, Willow Geist acts as both the expendable sacrifice and our life-buffer, growing with +1/+1 counters as cards leave the graveyard and refunding our life total when it dies to feed the Citadel's cost once more.