Karlov of the Ghost Council, Animation Module, Ajani's Welcome, and Ashnod's Altar

Prerequisites

• Karlov of the Ghost Council on the battlefield
• Animation Module on the battlefield
• Ajani's Welcome on the battlefield
• Ashnod's Altar on the battlefield
• You have a way to cause a creature to enter the battlefield under your control

Steps

1. Cause a creature to enter the battlefield under your control
2. Ajani's Welcome triggers, causing you to gain 1 life
3. Karlov triggers, putting two +1/+1 counters on itself
4. Animation Module triggers, causing you to pay to create a 1/1 Servo artifact creature token
5. The Servo enters the battlefield, triggering Ajani's Welcome
6. Holding priority, activate Ashnod's Altar by sacrificing the Servo, adding
7. Resolve the Ajani's Welcome trigger, causing you to gain 1 life
8. Repeat from step 3

Results

• Infinite +1/+1 counters on Karlov
• Infinite colorless mana
• Infinite creature tokens
• Infinite death triggers
• Infinite ETB
• Infinite lifegain
• Infinite lifegain triggers
• Infinite LTB
• Infinite sacrifice triggers