Tombstone Stairwell, and South Wind Avatar

Prerequisites

• Tombstone Stairwell on the battlefield
• South Wind Avatar on the battlefield

Steps

1. At the beginning of each upkeep, Tombostone Stairwell's first ability triggers, causing each player to create a 2/2 Zombie creature token for each creature card in their graveyard
2. At the beginning of each end step, Tombstone Stairwell's second ability triggers, destroying all tokens created by it
3. When the token(s) die, South Wind Avatar's first ability triggers that many times, causing you to gain that much life
4. South Wind Avatar's second ability triggers that many times, causing each opponent to lose that much life
5. Repeat during each turn

Results

• Near-infinite ETB
• Near-infinite LTB
• Near-infinite death triggers
• Near-infinite lifegain
• Near-infinite lifegain triggers
• Near-infinite lifeloss