Mortuary + Woe Strider + Bolas's Citadel + Tarpan

Mortuary

Woe Strider

Bolas's Citadel

Tarpan

How it works

1. Activate Woe Strider by sacrificing Tarpan.
2. When Tarpan dies, it and Mortuary triggers.
3. Resolve the Mortuary trigger, putting Tarpan from your graveyard onto the top of your library.
4. Resolve the Tarpan trigger, causing you to gain 1 life
5. Resolve the Woe Strider ability.
6. Cast Tarpan from the top of your library by paying 1 life due to Bolas's Citadel.
7. Repeat.

This elegant loop centers on Bolas's Citadel, which turns the top of your library into your hand and replaces mana costs with life payments, allowing you to continuously cast your creatures from the top. To sustain this, Woe Strider acts as the sacrifice outlet that feeds the engine while smoothing your draws with its scry ability. Whenever Woe Strider sacrifices Tarpan, Mortuary instantly catches the tiny beast in the graveyard and puts it right back onto the top of your library. Finally, the life lost casting Tarpan from the top via Bolas's Citadel is completely offset by the lifegain trigger when Tarpan dies, creating a self-sustaining loop that generates infinite deaths and sacrifice triggers.