Mortuary + Ashnod's Altar + Crimson Kobolds + Gwenom, Remorseless

Mortuary

Ashnod's Altar

Crimson Kobolds

Gwenom, Remorseless

How it works

1. Activate Ashnod's Altar by sacrificing Crimson Kobolds
2. When Crimson Kobolds dies, Mortuary triggers, putting Crimson Kobolds from your graveyard onto the top of your library.
3. Cast Crimson Kobolds from the top of your library by paying 0 life.
4. Repeat.

This clever engine uses Gwenom, Remorseless to turn the top of your library into an active hand, allowing you to cast Crimson Kobolds for zero mana since its mana value is zero. Once the Kobolds are on the battlefield, Ashnod's Altar steps in to sacrifice them, generating a steady stream of colorless mana while sending the creature straight to the graveyard. That death triggers Mortuary, which neatly recycles the Crimson Kobolds right back to the top of your library so Gwenom can let you cast them all over again.