Cast Change of Heart with buyback by paying {W}.
Storm-Kiln Artist triggers, creating a Treasure token.
Resolve Change of Heart.
Activate the Treasure by tapping and sacrificing it, adding {W}.
Repeat.

Infinite storm count

Infinite magecraft triggers

Samut, the Driving Force

Storm-Kiln Artist

Change of Heart

Activate up to five lands you control by tapping them, adding at least {3}{W}.
Cast Change of Heart with buyback by paying {3}{W}, targeting Peregrine Drake.
Orvar's first ability triggers, creating a token copy of Peregrine Drake.
The Peregrine Drake token enters the battlefield, untapping up to five lands.
Resolve Change of Heart, returning it to your hand.
Repeat.
If you control up to five lands that can tap to produce at least {4}{W}, this combo nets infinite mana, which you can then target any creatures you control in step 2 to create infinite token copies of them.

Infinite copies of creatures you control

Infinite creature tokens

Infinite ETB

Infinite mana lands you control can produce

Infinite untap of lands you control

Orvar, the All-Form

Peregrine Drake

Activate Will by tapping it, causing white and blue spells you cast this turn to cost at least {3} less.
Activate a creature by tapping it, adding {W}.
Cast Change of Heart with buyback by paying {W}.
Chakram Retriever triggers, untapping the mana-producing creature.
Resolve Change of Heart.
Repeat from step 2.

Will, Scion of Peace

Chakram Retriever

Csat Change of Heart with buyback by paying {3}{W}.
Each Stormsplitter you control triggers, creating that many token copies of Stormsplitter.
Resolve Change of Heart, returning it to your hand.
If you control at least eight Stormsplitters, activate Phyrexian Altar four times by sacrificing four Stormsplitter tokens, adding {3}{W}.
Repeat.

Infinite LTB

Infinite colored mana

Infinite sacrifice triggers

Infinite death triggers

Infinite creature tokens with haste

Stormsplitter

Phyrexian Altar

If able, activate Throne of Eldraine's first ability by tapping it, adding {W}{W}{W}{W} that can only be spent to cast white monocolored spells.
Cast Change of Heart with buyback by paying {3}{W}, targeting Displacer Kitten.
Displacer Kitten triggers, blinking Throne of Eldraine. Choose "White" as it enters the battlefield.
Resolve Change of Heart, returning it to your hand.
Repeat.

Displacer Kitten

Throne of Eldraine

Activate up to seven lands you control by tapping them, adding at least {3}{W}.
Cast Change of Heart with buyback by paying {3}{W}, targeting Great Whale.
Orvar's first ability triggers, creating a token copy of Great Whale.
The Great Whale token enters the battlefield, untapping up to seven lands.
Resolve Change of Heart, returning it to your hand.
Repeat.
If you control up to seven lands that can tap to produce at least {4}{W}, this combo nets infinite mana, which you can then target any creatures you control in step 2 to create infinite token copies of them.

Great Whale

Activate up to seven lands you control by tapping them, adding at least {3}{W}.
Cast Change of Heart with buyback by paying {3}{W}, targeting Palinchron.
Orvar's first ability triggers, creating a token copy of Palinchron.
The Palinchron token enters the battlefield, untapping up to seven lands.
Resolve Change of Heart, returning it to your hand.
Repeat.
If you control up to seven lands that can tap to produce at least {4}{W}, this combo nets infinite mana, which you can then target any creatures you control in step 2 to create infinite token copies of them.

Palinchron

At the beginning of your precombat main phase, There and Back Again triggers, creating a legendary 6/6 Smaug creature token, and causing you to sacrifice There and Back Again.
Cast Change of Heart with buyback by paying {3}{W}, targeting the Smaug token.
Orvar's first ability triggers, creating a copy of the Smaug token.
Put the new Smaug token into your graveyard due to the legend rule.
When Smaug dies, it triggers, creating fourteen Treasure tokens.
Resolve Change of Heart from step 2, returning it to your hand.
Activate four Treasures by tapping and sacrificing them, adding {3}{W}.
Repeat from step 2.
Once you have infinite colored mana, you may instead target any other creature(s) you control using Change of Heart, to create infinite tokens of them using Orvar.

Infinite Treasure tokens

There and Back Again

Activate Empowered Autogenerator by tapping it, putting a charge counter on it and adding {W} for each charge counter on it.
Cast Change of Heart with buyback by paying {3}{W}.
Shantotto triggers, giving it +4/+0 until end of turn and causing you to draw a card.
Resolve Change of Heart.
Activate Mind Over Matter by discarding a card, untapping Empowered Autogenerator.
Repeat.

Infinite self-discard triggers

Infinite draw triggers

Infinite looting

Near-infinite storm count

Near-infinite magecraft triggers

Near-infinite colored mana

Near-infinite charge counters on a permanent

Near-infinitely powerful creature until end of turn

Shantotto, Tactician Magician

Mind Over Matter

Empowered Autogenerator

Cast Change of Heart with buyback by paying {0} due to Aang's cost reduction, returning Change of Heart to your hand.
Repeat.

Combos with "Change of Heart"