Extraction Specialist + Leonin Relic-Warder + Biotransference + Phyrexian Altar

Extraction Specialist
Leonin Relic-Warder
Biotransference
Phyrexian Altar

Requires
Leonin Relic-Warder in hand. All other permanents on the battlefield. You have at least 2 life. ww available.
Steps
  1. Cast Leonin Relic-Warder by paying ww
  2. Biotransference triggers, causing you to lose 1 life and create a 2/2 Necron Warrior token
  3. Leonin Relic-Warder's ETB ability triggers, exiling Extraction Specialist
  4. Activate Phyrexian Altar by sacrificing Leonin Relic-Warder, adding one mana of any color
  5. Leonin Relic-Warder's LTB ability triggers, returning Extraction Specialist from exile to the battlefield
  6. Extraction Specialist enters the battlefield, returning Leonin Relic-Warder from your graveyard to the battlefield
  7. Repeat from step 3
Results
Infinite colored mana. Infinite ETB. Infinite LTB. Infinite death triggers. Infinite sacrifice triggers.