Activate Cauldron of Souls by tapping it, targeting Threefold Thunderhulk.
Activate Clock of Omens by tapping Threefold Thunderhulk and the other creature that enters with +1/+1 counter(s), untapping Kuldotha Forgemaster.
Activate Kuldotha Forgemaster by tapping it and sacrificing Threefold Thunderhulk, the creature entering with +1/+1 counter(s) and another artifact.
When Threefold Thunderhulk and the other creature die, their persist abilities trigger, returning them from your graveyard to the battlefield. The -1/-1 counters placed upon them will be removed by the +1/+1 counter(s) placed on them as they enter the battlefield.
When Threefold Thunderhulk enters, it triggers, creating two 1/1 Gnome artifact creature tokens.
Resolve the Kuldotha Forgemaster ability, searching your library for an artifact card and putting it onto the battlefield.
Activate Clock of Omens by tapping two Gnomes, untapping Cauldron of Souls.
Repeat.

Infinite LTB

Infinite ETB

Infinite death triggers

Put all artifacts from your library onto the battlefield

Artifact Creature That Enters With +1/+1 Counter(s)

Kuldotha Forgemaster

Clock of Omens

Cauldron of Souls

Threefold Thunderhulk

Activate Timestream Navigator by paying {2}{U}{U}, tapping it and putting it from the battlefield onto the bottom of your library, causing you to take an extra turn after this one.
Activate Transmutation Font's first ability by tapping it, creating a Food, a Clue and a Treasure token.
Activate Kuldotha Forgemaster by tapping it, sacrificing the Food, the Clue and the Treasure, putting Timestream Navigator from your library onto the battlefield.
Repeat each turn.

Infinite turns

Transmutation Font

Timestream Navigator

Academy Manufactor

Encroaching Mycosynth

Activate Transmutation Font's first ability by tapping it, creating a Food, a Clue and a Treasure token.
Activate Kuldotha Forgemaster by tapping it, sacrificing the Food, the Clue and the Treasure, putting Machine God's Effigy from your library onto the battlefield.
If you don't have the city's blessing, Machine God's Effigy gives you the city's blessing.
Activate Machine God's Effigy by paying {2}{U}{U}, tapping it and putting it from the battlefield onto the bottom of your library, causing you to take an extra turn after this one.
Repeat each turn.

Machine God's Effigy

Combos with "Kuldotha Forgemaster"