Magmatic Galleon + Ghirapur Aether Grid + Primal Vigor

Magmatic Galleon

Ghirapur Aether Grid

Primal Vigor

How it works

1. Give an opponent's creature indestructible, if needed.
2. Activate Ghirapur Aether Grid by tapping two artifacts you control, dealing 1 damage to an indestructible creature an opponent controls.
3. If the creature has less than 0 toughness, Magmatic Galleon's second ability triggers, creating two Treasure artifact tokens.
4. Repeat from step 2.

This loop relies on dealing excess noncombat damage to an indestructible opponent's creature (or one with low toughness) using the activated ability of Ghirapur Aether Grid. Each time that damage is dealt, Magmatic Galleon's triggered ability recognizes the excess damage being dealt to an opponent's creature and generates a Treasure token. Because Primal Vigor doubles any tokens that would be created, that single trigger yields two Treasures instead of one. You can then use two of those newly created tokens to pay for Ghirapur Aether Grid's activation cost, fueling an endless cycle that produces infinite tapped Treasure tokens and infinite artifact enters-the-battlefield triggers.