Endless Cockroaches + Deathrender + Phyrexian Altar

Endless Cockroaches

Deathrender

Phyrexian Altar

How it works

1. Activate Phyrexian Altar by sacrificing Endless Cockroaches, adidng one mana of any color.
2. Endless Cockroaches dies, triggering itself and Deathrender.
3. Resolve the Endless Cockroaches trigger, returning it from your graveyard to your hand.
4. Resolve the Deathrender trigger, putting Endless Cockroaches onto the battlefield from your hand, and attaching Deathrender to it.
5. Repeat.