You have enough mana to cast the earthbend creature.
Steps
Cast the earthbend creature by paying its mana cost.
When the creature enters, it triggers, earthbending the creature, as it's an artifact due to
Mycosynth Lattice, thus making it also a land due to
Toph.
Activate
Krark-Clan Ironworks by sacrificing the earthbent creature.
When the creature dies, it triggers, returning it from your graveyard to the battlefield tapped.
When the creature enters, it triggers, earthbending the creature, as it's an artifact due to
Mycosynth Lattice, thus making it also a land due to
Toph.
Repeat from step 3.
Notes
Depending on the earthbend creature used, you may receive additional results. There may also be needed prerequisites that are specific for each card (such as Bumi, King of Three Trials which requires a Lesson in your graveyard).
Results
Infinite artifact ETB.
Infinite artifact LTB.
Infinite artifact sacrifice triggers.
Infinite colored mana.
Infinite colorless mana.
Infinite creature ETB.
Infinite creature LTB.
Infinite creature sacrifice triggers.
Infinite death triggers.
Infinite landfall triggers.
Metadata
In 948 decks according to EDHREC.
Bracket Tag
This combo has been estimated to be Exhibition (Bracket 1+).