Activate a creature by tapping it, adding at least {U}.
Activate Harmonized Trio by tapping it and two other creatures you control, causing it to become prepared.
Cast a copy of Brainstorm by paying {U}.
Metallurgic Summonings triggers, creating a creature token.
When the creature token enters, Intruder Alarm triggers, untapping all creatures.
Resolve Brainstorm, causing you to draw three cards and put two cards from your hand onto the top of your library.
Repeat.

Infinite card draw

Infinite draw triggers

Near-infinite creature ETB

Near-infinite creature tokens

Near-infinite magecraft triggers

Near-infinite storm count

Near-infinite untap of all creatures

Intruder Alarm

Harmonized Trio // Brainstorm

Metallurgic Summonings

Cast Mythos of Illuna by paying {2}{U}{U}, targeting anything but Metallurgic Summonings.
In response, cast Radiate by paying {3}{R}{R}.
Metallurgic Summonings triggers, creating a 5/5 Construct artifact creature token.
Resolve Radiate, creating copies of Mythos of Illuna that target each permanent besides the original target.
Resolve all copies of Mythos of Illuna besides the original, creating token copies of each permanent besides the original target, bringing the total number of artifacts you control to at least six.
Activate any copy of Metallurgic Summonings by paying {3}{U}{U}, returning all instant and sorcery cards from your graveyard to your hand.
Activate the token lands or other mana-producing permanents created in step 3 by tapping them, adding at least {6}{U}{U}{R}{R}.
Repeat from step 2, doubling the number of copies created in step 4 each repetition.

Infinite copies of all permanents

Infinite creature tokens

Infinite magecraft triggers

Infinite mana permanents on the battlefield can produce

Infinite storm count

Return all instant and sorcery cards from your graveyard to your hand

Mythos of Illuna

Radiate

Activate The Tenth Doctor by paying {7}, removing all time counters from Reality Strobe.
Reality Strobe triggers, causing you to cast it from exile without paying its mana cost.
Metallurgic Summonings triggers, creating a creature token.
When the creature token enters, Mana Echoes triggers, adding {C} for each creature you control that shares a creature type with the token.
Resolve Reality Strobe.
Repeat.

Combos with "Metallurgic Summonings"