Mortuary + Umbral Collar Zealot + Bolas's Citadel + Crookshank Kobolds

Mortuary

Umbral Collar Zealot

Bolas's Citadel

Crookshank Kobolds

How it works

1. Activate Umbral Collar Zealot by sacrificing Crookshank Kobolds
2. When Crookshank Kobolds dies, Mortuary triggers, putting Crookshank Kobolds from your graveyard onto the top of your library.
3. Resolve the Umbral Collar Zealot ability.
4. Cast Crookshank Kobolds from the top of your library by paying 0 life.
5. Repeat.

This loop relies on casting zero-mana creatures straight from the top of your library using Bolas's Citadel, bypassing traditional mana costs by paying life instead. When you sacrifice Crookshank Kobolds to Umbral Collar Zealot, Mortuary instantly intercepts the creature as it hits the graveyard, neatly tucking it back onto the top of your library so the Citadel can play it once more. Meanwhile, Umbral Collar Zealot's surveil ability helps manipulate your topdeck if needed, turning your life total into an endless engine for infinite storm count, enter-the-battlefield triggers, and death triggers.