Mortuary + Bolas's Citadel + Proper Burial + Goblin Firestarter

Mortuary

Bolas's Citadel

Proper Burial

Goblin Firestarter

How it works

1. Activate Goblin Firestarter by sacrificing it.
2. When Goblin Firestarter dies, Mortuary and Proper Burial trigger.
3. Resolve the Mortuary trigger, putting Goblin Firestarter from your graveyard onto the top of your library.
4. Resolve the Proper Burial trigger, causing you to gain 1 life
5. Resolve the Goblin Firestarter ability.
6. Cast Goblin Firestarter from the top of your library by paying 1 life.
7. Repeat.

This clever loop turns a humble Goblin Firestarter into an engine of endless attrition, fueled entirely by life rather than mana. With Bolas's Citadel granting you permission to cast the goblin straight from the top of your library, Mortuary immediately intercepts it upon death to tuck it right back where it came from. Meanwhile, Proper Burial cushions the life cost of Bolas's Citadel by refunding the toughness of the dying sacrifice every single iteration.