Rex, Cyber-Hound, Pili-Pala, and Nantuko Elder

Prerequisites

• Rex, Cyber-Hound on the battlefield
• Pili-Pala in exile
• Nantuko Elder in exile
• Rex does not have summoning sickness
• Nantuko Elder and Pili-Pala exiled with a brain counter on them

Steps

1. Activate Rex using Nantuko Elder's ability by tapping it, adding
2. Activate Rex using Pili-Pala's ability by paying and untapping it, adding one mana of any color
3. Repeat

Results

• Infinite colored mana
• Infinite colorless mana