Urza, Prince of Kroog + Metalworker + Retreat to Coralhelm + Razortide Bridge

Urza, Prince of Kroog

Metalworker

Retreat to Coralhelm

Razortide Bridge

How it works

1. Activate Metalworker by tapping it and revealing at least three artifact cards from your hand, adding at least six C.
2. Activate Urza by paying 6, creating a token copy of Razortide Bridge that is a 1/1 Soldier.
3. When the Razortide Bridge token enters the battlefield, Retreat to Coralhelm triggers, untapping Metalworker.
4. Repeat.
5. If you have four or more artifact cards in hand, this combo nets infinite colorless mana, and you may target any artifact you control to get infinite copies of them.

This dazzling loop relies on Metalworker's massive mana generation, which is easily fueled when you have a handful of artifacts. By channeling that surplus into Urza, Prince of Kroog, you can pay six mana to forge a 1/1 Soldier token copy of Razortide Bridge. Because that token is a land hitting the battlefield, it triggers Retreat to Coralhelm, whose landfall ability untaps Metalworker so you can repeat the process. As long as Metalworker reveals enough cards to net more than the six mana Urza demands, you generate infinite colorless mana while also creating infinitely large armies of artifact creatures and copies of any artifacts you control.