Activate Fire Nation Palace's second ability by paying {1}{R} and tapping it, giving Hellkite Charger firebending 4 until end of turn.
Declare Hellkite Charger as an attacker, triggering it and its firebending ability twice.
Resolve both Hellkite Charger firebending triggers, adding eight {R}.
Resolve the first Hellkite Charger trigger, choosing not to pay.
Resolve the second Hellkite Charger trigger, causing you to pay {5}{R}{R} to untap all attacking creatures and to get an additional combat phase after this one.
Repeat from step 2.

Infinite combat phases

Infinite red mana

Hellkite Charger

Fire Nation Palace

Isshin, Two Heavens as One

Activate Fire Nation Palace's second ability by paying {1}{R} and tapping it, giving The Incredible Hulk firebending 4 until end of turn.
Declare The Incredible Hulk as an attacker. Its firebending ability triggers, adding {R}{R}{R}{R}.
Holding priority, activate Pyrohemia by paying {R}, dealing 1 damage to each creature and player.
The Incredible Hulk triggers, putting a +1/+1 counter on it, untapping it and giving you an additional combat phase after this one.
Repeat from step 2 each combat phase.

Near-infinite combat phases

Near-infinite damage to all players

Near-infinite +1/+1 counters on a creature

Bruce Banner // The Incredible Hulk

Pyrohemia

Activate Fire Nation Palace's second ability by paying {1}{R} and tapping it, giving The Incredible Hulk firebending 4 until end of turn.
Declare The Incredible Hulk as an attacker. Its firebending ability triggers, adding {R}{R}{R}{R}.
Holding priority, activate Walking Ballista's first ability by paying {4}, putting a +1/+1 counter on it.
Activate Walking Ballista's second ability by removing a +1/+1 counter from it, dealing 1 damage to The Incredible Hulk.
The Incredible Hulk triggers, putting a +1/+1 counter on it, untapping it and giving you an additional combat phase after this one.
Repeat from step 2 each combat phase.

Infinite +1/+1 counters on a creature

Walking Ballista

Combos with "Fire Nation Palace"