Mortuary + Bolas's Citadel + Goblin Firestarter + Venerated Stormsinger

Mortuary

Bolas's Citadel

Goblin Firestarter

Venerated Stormsinger

How it works

1. Activate Goblin Firestarter by sacrificing it.
2. When Goblin Firestarter dies, Mortuary and Venerated Stormsinger trigger.
3. Resolve the Mortuary trigger, putting Goblin Firestarter from your graveyard onto the top of your library.
4. Resolve the Venerated Stormsinger trigger, causing you to gain 1 life and each opponent to lose 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 loop turns the top of your library into an endless armory, fueled directly by your own life total through Bolas's Citadel. Goblin Firestarter provides the sacrifice engine itself, dealing damage while reliably sliding back onto the top of your library via Mortuary's replacement-style trigger every time it dies. Meanwhile, Venerated Stormsinger sits on the board to capitalize on the carnage, turning every single recursion loop into a life-draining engine that comfortably offsets the life you pay to recast Goblin Firestarter off the Citadel.