Archangel of Thune, and Walking Ballista

Prerequisites

• Archangel of Thune on the battlefield
• Walking Ballista on the battlefield
• Walking Ballista has at least two +1/+1 counters on it
• You have a way to give Walking Ballista lifelink

Steps

1. Give Walking Ballista lifelink
2. Activate Walking Ballista's second ability by removing a +1/+1 counter from it, dealing 1 damage to any target and causing you to gain 1 life
3. Archangel of Thune triggers, putting a +1/+1 counter on each creature you control
4. Repeat from step 2

Results

• Infinite +1/+1 counters on all creatures you control except Walking Ballista
• Infinite damage
• Infinite lifegain
• Infinite lifegain triggers