Activate Ashnod's Altar by sacrificing Arcbound Worker, adding {C}{C}.
Arcbound Worker dies, triggering its modular ability, moving its +1/+1 counters onto Arcbound Reclaimer.
Activate Arcbound Reclaimer by removing a +1/+1 counter from it, putting Arcbound Worker on top of your library from your graveyard.
Cast Arcbound Worker from the top of your library by paying {1}.
Arcbound Worker enters the battlefield with a +1/+1 counter on it due to its modular ability.
Repeat.

Infinite colorless mana

Infinite death triggers

Infinite creature ETB

Infinite creature LTB

Infinite creature sacrifice triggers

Infinite storm count

Arcbound Reclaimer

Mystic Forge

Arcbound Worker

Ashnod's Altar

Activate Together Forever by paying {1}, targeting Arcbound Worker.
Activate Ashnod's Altar by sacrificing Acrbound Worker, adding {C}{C}.
Arcbound Worker dies, triggering its modular ability and Together Forever.
Resolve the Arcbound Worker trigger, moving its +1/+1 counters onto another artifact creature.
Resolve the Together Forever trigger, returning Arcbound Worker from your graveyard to your hand.
Cast Arcbound Worker by paying {1}, which enters with a +1/+1 counter on it.
Repeat.

Infinite +1/+1 counters on certain creatures

Together Forever

Activate Krark-Clan Ironworks by sacrificing Arcbound Worker, adding {C}{C}.
Arcbound Worker dies, triggering its modular ability, moving its +1/+1 counters onto Arcbound Reclaimer.
Activate Arcbound Reclaimer by removing a +1/+1 counter from it, putting Arcbound Worker on top of your library from your graveyard.
Cast Arcbound Worker from the top of your library by paying {1}.
Arcbound Worker enters the battlefield with a +1/+1 counter on it due to its modular ability.
Repeat.

Krark-Clan Ironworks

Kill Arcbound Worker.
When Arcbound Worker dies, its persist ability triggers, returning Arcbound Worker from your graveyard to the battlefield. It will have no counters on it due to its modular ability.
Arcbound Worker dies as a state-based action due to having 0 toughness
Repeat from step 2.

Infinite artifact ETB

Infinite artifact LTB

Draw the game

Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight

Activate Arcbound Worker by paying {1}{U}, blinking it.
Arcbound Worker leaves and reenters the battlefield, causing it to enter with a +1/+1 counter due to its modular ability, and triggering The Ooze and Deadeye Navigator's soulbond ability.
Resolve Deadeye Navigator's trigger, repairing it and Arcbound Worker
Resolve The Ooze's trigger, creating a Mutagen token for each +1/+1 counter that was on Arcbound Worker when it left the battlefield.
Activate Urza's first ability twice by tapping Arcbound Worker and a Mutagen, adding {U}{U}.
Repeat.

Combos with "Arcbound Worker"