Saheeli, the Sun's Brilliance, Mana Echoes, Mycosynth Lattice, and Great Oak Guardian

Prerequisites

• Saheeli, the Sun's Brilliance on the battlefield
• Mana Echoes on the battlefield
• Mycosynth Lattice on the battlefield
• Great Oak Guardian on the battlefield
• Saheeli does not have summoning sickness
• available

Steps

1. Activate Saheeli by paying and tapping it, creating a token copy of Great Oak Guardian with haste
2. When the token Great Oak Guardian enters the battlefield, it and Mana Echoes trigger
3. Resolve the Great Oak Guardian trigger, untapping all creatures you control and giving them +2/+2 until end of turn
4. Resolve the Mana Echoes trigger, adding for each creature you control that shares a creature type with Great Oak Guardian
5. Repeat

Results

• Infinite ETB
• Infinite colored mana
• Infinite colorless mana
• Infinite creature tokens with haste
• Infinite untap of creatures you control
• Infinitely large creatures you control until end of turn