Filigree Sages + Prototype Portal + Razortide Bridge + Tiller Engine + Agatha of the Vile Cauldron

Filigree Sages

Prototype Portal

Razortide Bridge

Tiller Engine

Agatha of the Vile Cauldron

How it works

1. Activate Prototype Portal by paying 0 and tapping it, creating a token copy of Razortide Bridge.
2. When Razortide Bridge enters the battlefield, Tiller Engine triggers, untapping it.
3. Activate the Razortide Bridge token by tapping it, adding .
4. Activate Filigree Sages by paying , untapping Prototype Portal.
5. Repeat.

This ingenious loop turns a modest copy machine into a self-sustaining mana engine. By imprinting Razortide Bridge onto Prototype Portal, you can churn out copies of the land for free; thanks to its indestructible nature, it doesn't even mind landing in a pile. As each copy enters the battlefield tapped, Tiller Engine swoops in with its triggered ability to immediately untap it. Meanwhile, Filigree Sages stands ready to untap your Prototype Portal using the blue mana generated by your newly minted bridge. While Agatha of the Vile Cauldron isn't strictly required for this specific iteration to go infinite, her presence helps grease the wheels by discounting creature-based activated abilities whenever you need to streamline your mana costs.