Activate your commander using the ability granted to it by Street Urchin by paying {1} and sacrificing another creature or artifact, dealing 2 damage to Smaug due to Jaya, Venerated Firemage.
Smaug triggers, creating two Treasure tokens.
Activate a Treasure by tapping and sacrificing it, adding {1}.
Repeat.

Infinite artifact ETB

Infinite artifact LTB

Infinite artifact sacrifice triggers

Smaug the Impenetrable

Street Urchin

Jaya, Venerated Firemage

Activate Deathless Angel twice by paying {W}{W}{W}{W}, giving two creatures an opponent controls indestructible until end of turn.
Deal noncombat damage to one of the indestructible creatures, dealing an increased amount of damage instead due to Jaya, Venerated Firemage.
Toralf triggers, dealing an amount of damage over the excess damage to the second indestructible creature due to Jaya, Venerated Firemage.
Toralf triggers, dealing an amount of damage over the excess damage to the first indestructible creature due to Jaya, Venerated Firemage.
Repeat from step 3 an arbitrarily large number of times.
Resolve a Toralf trigger, dealing infinite damage to any target.

Infinite damage to one opponent

Toralf, God of Fury // Toralf's Hammer

Deathless Angel

Activate Deathbringer Thoctar by removing a +1/+1 counter from it, putting two +1/+1 counters on it due to Vigor.
Activate Deathbringer Thoctar by removing a +1/+1 counter from it, dealing 2 damage to any target.
Repeat as desired.

Infinite damage

Infinite +1/+1 counters on creatures you control

Vigor

Deathbringer Thoctar

Combos with "Jaya, Venerated Firemage"