Mortuary + Bolas's Citadel + Viscera Seer + Panicked Bystander // Cackling Culprit

Mortuary

Bolas's Citadel

Viscera Seer

Panicked Bystander // Cackling Culprit

How it works

1. Activate Viscera Seer by sacrificing it.
2. When Viscera Seer dies, Mortuary and Panicked Bystander // Cackling Culprit trigger.
3. Resolve the Mortuary trigger, putting Viscera Seer from your graveyard onto the top of your library.
4. Resolve the Panicked Bystander // Cackling Culprit trigger, causing you to gain 1 life
5. Resolve the Viscera Seer ability.
6. Cast Viscera Seer from the top of your library by paying 1 life.
7. Repeat.

This clever engine lets you loop Viscera Seer indefinitely by using Bolas's Citadel to cast it straight off the top of your library for a mere 1 life instead of its mana cost. Whenever you sacrifice your seer, Mortuary steps in to instantly recycle it right back to the top of your library, ensuring you never run out of fodder. Meanwhile, Panicked Bystander // Cackling Culprit cushions the life payment from the citadel by effortlessly offsetting it with infinite lifegain every single time a creature dies.