Agatha of the Vile Cauldron, Silvanus's Invoker, and New Horizons

Prerequisites

• Agatha of the Vile Cauldron on the battlefield
• Silvanus's Invoker on the battlefield
• New Horizons on the battlefield

Steps

1. Activate the land with New Horizons attached by tapping it, adding two mana of any color
2. Activate Silvanus's Invoker by paying , untapping the land and causing it to become an 8/8 Elemental with trample and haste in addition to its other types until end of turn
3. Repeat

Results

• Infinite colored mana
• Infinite mana lands you control can produce
• Infinite power and toughness for most creatures you control until end of turn
• Infinite untap of lands you control