Mortuary + Krark-Clan Ironworks + Bolas's Citadel + Ornithopter

Mortuary

Krark-Clan Ironworks

Bolas's Citadel

Ornithopter

How it works

1. Activate Krark-Clan Ironworks by sacrificing Ornithopter
2. When Ornithopter dies, Mortuary triggers, putting Ornithopter from your graveyard onto the top of your library.
3. Cast Ornithopter from the top of your library by paying 0 life.
4. Repeat.

This elegant engine turns a humble zero-mana artifact into a boundless well of resources by exploiting the interaction between your library and graveyard. With Bolas's Citadel allowing you to freely cast spells directly from the top of your library by paying life instead of mana, Ornithopter becomes an endlessly repeatable loop piece. You simply sacrifice the creature to Krark-Clan Ironworks to generate colorless mana, which then triggers Mortuary to place Ornithopter right back on top of your library so Bolas's Citadel can play it once more. Because Ornithopter costs zero mana, the life payment via Bolas's Citadel is zero as well, letting you safely cycle the mechanical flyer infinitely to farm an enormous storm count, death triggers, and colorless mana.