Artifact with MV<=2 that has a generic mana cost in hand.
All other permanents on the battlefield.
Steps
Activate
Evereth by sacrificing
Aether Channeler.
Activate
Mana Vault by tapping it, adding ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) .
Cast the other artifact with MV<=2 by paying at most ({2} magic symbol) .
Teshar triggers, returning
Aether Channeler from your graveyard to the battlefield.
When
Aether Channeler enters the battlefield, it triggers, returning
Mana Vault from the battlefield to your hand.
Activate
Evereth by sacrificing
Aether Channeler.
Cast
Mana Vault by paying ({0} magic symbol) .
Teshar triggers, returning
Aether Channeler from your graveyard to the battlefield.
When
Aether Channeler enters the battlefield, it triggers, returning the other artifact from the battlefield to your hand.
Repeat.
Notes
If you have a way to kill
Evereth and ({1} magic symbol) ({BR} magic symbol) available, you can do so after putting a significant amount of +1/+1 counters on it to deal damage to each opponent using its second ability.
Results
Infinite +1/+1 counters on a creature.
Infinite creature ETB.
Infinite creature LTB.
Infinite creature sacrifice triggers.
Infinite death triggers.
Infinite storm count.
Infinite damage.
Metadata
In 0 decks according to EDHREC.
Bracket Tag
This combo has been estimated to be Powerful (Bracket 3+).