If The Aetherspark is in your graveyard, activate Emry by tapping it, allowing you to cast The Aetherspark from your graveyard this turn.
Cast The Aetherspark either from your hand or from your graveyard by paying {4}.
Activate Brass Squire by tapping it, attaching The Aetherspark to a creature you control that has exactly 6 power.
Deal combat damage to an opponent using the creature that has The Aetherspark attached, triggering The Aetherspark, putting six loyalty counters on it.
Activate The Aetherspark's third loyalty ability by removing ten loyalty counters from it, adding ten {R}.
The Aetherspark is put into your graveyard as a state-based action due to having 0 loyalty.
Activate Aggravated Assault by paying {3}{R}{R}, causing you to untap all creatures you control and to get an additional combat and main phase after this one.
Repeat.

Infinite colored mana

Infinite storm count

Infinite combat phases

Infinite untap of creatures you control

Infinite mana creatures you control can produce

Infinite combat damage

The Aetherspark

Brass Squire

Aggravated Assault

Emry, Lurker of the Loch

Declare a creature you control that cannot be blocked by an opponent as an attacker.
Holding priority, activate Brass Squire by tapping it, attaching Assimilation Aegis to the attacking creature.
Assimilation Aegis' second ability triggers, causing the creature to become a copy of Medomai the Ageless.
Deal combat damage with the creature.
The creature triggers, causing you to take an extra turn after this one.
Move to your next turn.
Activate Assimilation Aegis' equip ability by paying {2}, attaching it to any other creature you control except Brass Squire.
Assimilation Aegis' second ability triggers, causing the creature to become a copy of Medomai the Ageless.
Repeat.

Infinite turns

Lock

Medomai the Ageless

Assimilation Aegis

Declare any other creature as an attacker.
Holding priority, activate Brass Squire by tapping it, attaching Dinosaur Headdress to the attacking creature, and causing the creature to become a copy of Medomai the Ageless.
Deal combat damage using the creature.
The creature triggers, causing you to take an extra turn after this one.
Move to your postcombat main phase.
Activate Dinosaur Headdress' equip ability by paying {2}, attaching it to Brass Squire.
Repeat each turn.

Paleontologist's Pick-Axe // Dinosaur Headdress

At the beginning of your combat phase, Ayara triggers, returning The Aetherspark from your graveyard to the battlefield.
Activate Brass Squire by tapping it, attaching The Aetherspark to a creature you control that has power equal to 6.
Deal combat damage to an opponent using the creature that has The Aetherspark attached, triggering The Aetherspark, putting six loyalty counters on it.
Activate The Aetherspark's third loyalty ability by removing ten loyalty counters from it, adding ten {R}.
The Aetherspark is put into your graveyard as a state-based action due to having 0 loyalty.
Activate Aggravated Assault by paying {3}{R}{R}, causing you to untap all creatures you control and to get an additional combat and main phase after this one.
Repeat.

Infinite artifact ETB

Infinite artifact LTB

Infinite red mana

Ayara, Widow of the Realm // Ayara, Furnace Queen

Combos with "Brass Squire"