Activate a mana-producing creature by tapping it, adding at least {1}.
Activate The Jolly Balloon Man by paying {1} and tapping it, targeting the mana-producing creature.
Ertha Jo triggers, copying The Jolly Balloon Man's ability, targeting Zealous Conscripts.
Resolve the copy of The Jolly Balloon Man's ability, creating a token copy of Zealous Conscripts that is a 1/1 Balloon with haste.
When Zealous Conscripts enters the battlefield, it triggers, untapping The Jolly Balloon Man.
Resolve the Jolly Ballon Man ability from step 2, creating a token copy of the mana-producing creature that is a 1/1 Balloon with haste.
Activate the mana-producing creature token by tapping it, adding at least {1}.
Repeat from step 2.

Infinite LTB

Infinite ETB

Infinite sacrifice triggers

Infinite death triggers

Infinite creature tokens with haste

The Jolly Balloon Man

Ertha Jo, Frontier Mentor

Zealous Conscripts

Activate a mana-producing creature by tapping it, adding at least {1}.
Activate The Jolly Balloon Man by paying {1} and tapping it, targeting the mana-producing creature.
Ertha Jo triggers, copying The Jolly Balloon Man's ability, targeting Restoration Angel.
Resolve the copy of The Jolly Balloon Man's ability, creating a token copy of Restoration Angel that is a 1/1 Balloon with haste.
When Restoration Angel enters the battlefield, it triggers, blinking The Jolly Balloon Man.
Resolve the Jolly Ballon Man ability from step 2, creating a token copy of the mana-producing creature that is a 1/1 Balloon with haste.
Activate the mana-producing creature token by tapping it, adding at least {1}.
Repeat from step 2.

Restoration Angel

Activate Aphetto Alchemist by tapping it, targeting itself.
Ertha Jo's second ability triggers, copying Aphetto Alchemist's ability, targeting any other creature or artifact.
Resolve both Aphetto Alchemist abilities, untapping it and the other targeted creature or artifact.
Repeat.

Infinite mana artifacts you control can produce

Infinite mana creatures you control can produce

Infinite untap of artifacts you control

Infinite untap of creatures you control

Aphetto Alchemist

Activate Seeker of Skybreak by tapping it, targeting itself.
Ertha Jo's second ability triggers, copying Seeker of Skybreak's ability, targeting any other creature.
Resolve both Seeker of Skybreak abilities, untapping it and the other targeted creature.
Repeat.

Seeker of Skybreak

Activate Palladium Myr by tapping it, adding {C}{C}.
Activate Voltaic Key by paying {1} and tapping it, targeting Palladium Myr.
Ertha Jo's second ability triggers, copying Voltaic Key's ability, targeting Voltaic Key.
Resolve both Voltaic Key abilities, untapping it and Palladium Myr.
Repeat.

Infinite colorless mana

Infinite untap of artifact creatures you control

Infinite mana artifact creatures you control can produce

Palladium Myr

Voltaic Key

Activate Tidewater Minion's second ability by tapping it, targeting itself.
Ertha Jo's second ability triggers, copying Tidewater Minion's ability, targeting any other permanent.
Resolve both Tidewater Minion abilities, untapping it and the other targeted permanent
Repeat.

Infinite mana permanents you control can produce

Infinite untap of permanents you control

Tidewater Minion

Activate Liquimetal Torque by tapping it, giving the creature with a tap trigger the artifact type.
Activate Clock of Omens by tapping it and the creature with a tap trigger, targeting the creature.
Ertha Jo and the creature trigger.
Resolve the creature's trigger.
Resolve the Ertha Jo trigger, copying Clock of Omens' ability, targeting Clock of Omens.
Resolve both Clock of Omens  abilities, untapping it and the creature tapped in step 2.
Repeat from step 2.

Infinite triggers from the creature with a tap trigger

Creature That Triggers on Being Tapped

Clock of Omens

Liquimetal Torque

Activate Transmutation Font's first ability by tapping it, creating your choice of a Clue, Food or Blood artifact token.
Activate Clock of Omens by tapping the token and an artifact creature, targeting the artifact creature.
Ertha Jo's second ability triggers, copying Clock of Omens' ability, targeting Transmutation Font.
Resolve both Clock of Omens abilities, untapping Transmutation Font and the artifact creature.
Repeat.

Infinite tapped Food tokens

Infinite tapped Clue tokens

Infinite tapped Blood tokens

Transmutation Font

Activate Kenrith by paying {G}, targeting Crystalline Crawler.
Ertha Jo triggers, copying Kenrith's ability, targeting any creature you control.
Resolve both Kenrith abilities, putting a +1/+1 counter on Crystalline Crawler and any creature you control.
Activate Crystalline Crawler by removing a +1/+1 counter from it, adding {G}.
Repeat.

Infinite colored mana

Infinite lifegain triggers

Infinite lifegain

Infinite +1/+1 counters

Infinite card draw for any number of players

Put all creature cards from all graveyards onto the battlefield under your control

Infinite draw triggers for any number of opponents

Kenrith, the Returned King

Crystalline Crawler

Zirda, the Dawnwaker

Activate Metalworker by tapping it, revealing at least one artifact card from your hand and adding at least {C}{C}.
Activate Voltaic Key by paying {1} and tapping it, targeting Metalworker.
Ertha Jo's second ability triggers, copying Voltaic Key's ability, targeting Voltaic Key.
Resolve both Voltaic Key abilities, untapping it and Metalworker.
Repeat.

Metalworker

Activate Clock of Omens by tapping it and Oreskos Sun Guide, targeting Oreskos Sun Guide.
Ertha Jo triggers, copying Clock of Omens' ability, targeting Clock of Omens.
Resolve both Clock of Omens  abilities, untapping it and Oreskos Sun Guide.
Oreskos Sun Guide triggers, causing you to gain 2 life.
Repeat.

Oreskos Sun Guide

Mycosynth Lattice

Combos with "Ertha Jo, Frontier Mentor"