Impromptu Raid + Mortuary + Phyrexian Altar + Burning-Tree Emissary

Impromptu Raid

Mortuary

Phyrexian Altar

Burning-Tree Emissary

How it works

1. Activate Phyrexian Altar by sacrificing Burning-Tree Emissary, adding R/G.
2. When Burning-Tree Emissary dies, Mortuary triggers, putting Burning-Tree Emissary on top of your library from your graveyard.
3. Actviate Impromptu Raid by paying 2R/G, revealing Burning-Tree Emissary from the top of your library and putting it onto the battlefield.
4. When Burning-Tree Emissary enters the battlefield, it triggers, adding .
5. Repeat.