Infinite creature ETBInfinite lifegain triggersInfinite lifegainInfinite creature tokensInfinite +1/+1 counters on creatures you control
How it works
Gain life.
Archangel of Thune triggers, putting a +1/+1 counter on each creature you control.
Herd Baloth triggers, creating a creature token.
When the creature token enters the battlefield, Lunarch Veteran triggers, causing you to gain 1 life.
Repeat from step 2.
This loop starts rolling the moment you gain any amount of life, which immediately prompts Archangel of Thune to blanket your board with +1/+1 counters. Because Herd Baloth sees those counters being placed on itself, it responds by spawning a 4/4 green Beast token. That new arrival entering the battlefield triggers Lunarch Veteran (or its Luminous Phantom back face) to reward you with another point of life, feeding right back into Archangel of Thune to repeat the cycle indefinitely.