({0} magic symbol) plus the cost of the creature that earthbends available.
Steps
Cast the earthbending creature by paying its mana cost, causing it to enter as an artifact land creature due to
Mycosynth Lattice and
Toph.
When that creature enters, it earthbends, causing itself to become a land creature with haste, putting at least one +1/+1 counter on itself, and creating a delayed triggered ability.
Activate
Trenching Steed by sacrificing that creature.
When that creature dies, the delayed ability from step 2 triggers, causing it to return to the battlefield tapped as an artifact land creature.
Repeat from step 2 any number of times.
Resolve all activated abilities from
Trenching Steed.
Results
Infinite ETB.
Infinite LTB.
Infinite death triggers.
Infinite landfall triggers.
Infinite sacrifice triggers.
Metadata
In 1 deck according to EDHREC.
Bracket Tag
This combo has been estimated to be Exhibition (Bracket 1+).