Ivy, Gleeful Spellthief + Cloudstone Curio + Treachery Combo

Treachery in hand.

Aura with MV<=5 in hand or on the battlefield.

Ivy and Cloudstone Curio on the battlefield.

There's another creature on the battlefield.

You control up to five lands that can tap to produce plus enough mana to cast the other Aura spell after the lands are tapped twice.

available

Cast Treachery by paying , targeting another creature.

Ivy triggers, copying Treachery, with the copy targeting Ivy.

Resolve the copy of Treachery, attaching it to Ivy.

When the Treachery copy enters, it and Cloudstone Curio triggers.

Resolve the Treachery trigger, untapping up to five lands.

Resolve the Cloudstone Curio trigger, returning nothing to your hand.

Resolve the original Treachery, attaching it to the targeted creature and causing you to gain control of that creature.

When Treachery enters, it and Cloudstone Curio triggers.

Holding priority, activate up to five lands by tapping them, adding an amount of mana.

Resolve the Treachery trigger, untapping up to five lands.

Resolve the Cloudstone Curio trigger, returning the other Aura from the battlefield to your hand if it's on the battlefield. If it isn't on the battlefield, then return nothing to your hand.

Activate up to five lands by tapping them, adding an amount of mana.

Cast the other Aura by paying its mana cost, targeting another creature.

Ivy triggers, copying the Aura, with the copy targeting Ivy.

Resolve the copy of the Aura, attaching it to Ivy.

When the Aura copy enters, Cloudstone Curio triggers. Choose to return nothing to your hand.

Resolve the original Aura, attaching it to the targeted creature.

When the Aura enters, Cloudstone Curio triggers, returning the nontoken Treachery from the battlefield to your hand.

Repeat.

Gain control of all creatures

Infinite copies of a specific enchantment

Infinite mana lands you control can produce

Infinite storm count

Infinite untap of lands you control