Infernal Vessel + Valkyrie's Call + Phyrexian Altar

Infernal Vessel

Valkyrie's Call

Phyrexian Altar

How it works

1. Activate Phyrexian Altar by sacrificing Infernal Vessel, adding one mana of any color.
2. When Infernal Vessel dies, it triggers, returning itself from your graveyard to the battlefield as a Demon in addition to its other types.
3. Activate Phyrexian Altar by sacrificing Infernal Vessel, adding one mana of any color.
4. When Infernal Vessel dies, Valkyrie's Call triggers, returning Infernal Vessel from your graveyard to the battlefield as an Angel in additional to its other types.
5. Repeat.