You control at least one additional nontoken green creature.
Hua Tuo does not have summoning sickness.
Steps
During your precombat main phase, activate
Evereth by sacrificing the additional nontoken green creature.
When the creature dies,
Verdant Succession triggers.
Holding priority, activate
Hua Tuo by tapping it, putting the creature from your graveyard onto the top of your library.
Resolve the
Verdant Succession trigger, searching your library for the sacrificed creature and putting it onto the battlefield.
When the creature enters the battlefield,
Intruder Alarm triggers, untapping all creatures.
Resolve the
Evereth ability from step 1, putting a +1/+1 counter on it.
Repeat.
Notes
If you have a way to kill
Evereth and ({1} magic symbol) ({BR} magic symbol) available, you can do so after putting a significant amount of +1/+1 counters on it to deal damage to each opponent using its second ability.
Results
Infinite +1/+1 counters on a creature.
Infinite creature ETB.
Infinite creature LTB.
Infinite creature sacrifice triggers.
Infinite death triggers.
Infinite mana creatures you control can produce.
Infinite untap of creatures.
Infinite damage.
Metadata
In 0 decks according to EDHREC.
Bracket Tag
This combo has been estimated to be Exhibition (Bracket 1+).