Phyrexian Altar + Stitcher's Supplier + Underworld Breach

BR identity

Commander legal

The 3 combo pieces

• Phyrexian Altar
• Stitcher's Supplier
• Underworld Breach

How to execute it

1. Activate Phyrexian Altar by sacrificing Stitcher's Supplier, adding {B}.
2. Stitcher's Supplier dies, causing you to mill three cards.
3. Cast Stitcher's Supplier for its escape cost by paying {B} and exling three other cards from your graveyard.
4. Stitcher's Supplier enters the battlefield, causing you to mill three cards.
5. Repeat.

What the combo produces

• Infinite self-mill
• Near-infinite creature sacrifice triggers
• Near-infinite death triggers
• Near-infinite ETB
• Near-infinite LTB
• Near-infinite storm count