Mortuary + Phyrexian Dreadnought + Overgrowth Elemental + Gwenom, Remorseless

Mortuary

Phyrexian Dreadnought

Overgrowth Elemental

Gwenom, Remorseless

How it works

1. Cast Phyrexian Dreadnought from the top of your library by paying 1 life.
2. When Phyrexian Dreadnought enters, it triggers, causing you to sacrifice it.
3. When Phyrexian Dreadnought dies, Mortuary and Overgrowth Elemental trigger.
4. Resolve the Mortuary trigger, putting Phyrexian Dreadnought from your graveyard onto the top of your library.
5. Resolve the Overgrowth Elemental trigger, causing you to gain 1 life
6. Repeat.

This ingenious loop centers around Gwenom, Remorseless, whose attack ability lets you cast creature spells directly from the top of your library by paying life equal to their mana value. You use this to deploy Phyrexian Dreadnought for a single life, completely bypassing its steep sacrifice requirement because it immediately dies upon entering the battlefield. The moment it hits the graveyard, Mortuary quietly ensures it goes straight back to the top of your library instead of staying in the yard. Meanwhile, Overgrowth Elemental watches the carnage, providing a steady stream of life gain every time the Dreadnought perishes and completes the cycle.