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

Mortuary

Umbral Collar Zealot

Crimson Kobolds

Bolas's Citadel

How it works

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

This loop sets up an endless cycle of zero-cost casting and recycling using Bolas's Citadel, which lets you play Crimson Kobolds directly off the top of your library for zero life due to its mana value of zero. Once the Kobolds are on the battlefield, you feed them to Umbral Collar Zealot's activation, leveraging the surveil ability to tidy your topdeck if needed while sending the Kobolds straight to the graveyard. That death immediately awakens Mortuary, whose static trigger intercepts the creature and tucks it right back onto the top of your library, making it instantly accessible for the Citadel again.