Mortuary + Harvester of Souls + Phyrexian Marauder

Mortuary

Harvester of Souls

Phyrexian Marauder

How it works

1. Cast Phyrexian Marauder by paying 0.
2. Phyrexian Marauder enters and dies as a state-based action due to having 0 toughness, triggering Mortuary and Harvester of Souls.
3. Resolve the Mortuary trigger, putting Phyrexian Marauder from your graveyard onto the top of your library.
4. Resolve the Harvester of Souls trigger, causing you to draw a card, thus drawing Phyrexian Marauder from your library.
5. Repeat.

This clever loop relies on Phyrexian Marauder entering the battlefield with zero toughness when cast for free, which instantly sends it to the graveyard as a state-based action. Mortuary ensures the creature never stays in the grave by immediately recycling it to the top of your library, setting it up to be drawn right away by the card draw triggered from Harvester of Souls watching another nontoken creature die. Because Phyrexian Marauder's mana cost is zero, you can continuously cast, bin, and redraw it to generate infinite death triggers, enter-the-battlefield effects, and a massive storm count.