Roxanne, Starfall Savant, Basalt Monolith, and Court of Vantress

Prerequisites

• Roxanne, Starfall Savant on the battlefield
• Basalt Monolith on the battlefield
• Court of Vantress on the battlefield
• You are the monarch

Steps

1. At the beginning of your upkeep, Court of Vantress triggers, creating a token copy of Basalt Monolith
2. Activate the token Basalt Monolith's first ability by tapping it, adding
3. Roxanne's second ability triggers, adding
4. Activate the token Basalt Monolith's second ability by paying , untapping it
5. Repeat from step 2

Results

• Infinite colorless mana