Activate Selvala by paying and tapping it, adding at least 1.
Activate Umbral Collar Zealot twice by sacrificing Selvala and Slimefoot and Squee.
Activate Slimefoot and Squee by paying 1 and sacrificing a Saproling, returning it and Selvala from your graveyard to the battlefield.
When Slimefoot and Squee enters the battlefield, it triggers, creating a 1/1 Saproling creature token.
Repeat.
This elegant engine lets you cycle your entire board through the graveyard while generating boundless colored mana. By leveraging Tuktuk Rubblefort, your reanimated threats gain haste the moment they hit the board, allowing Selvala, Heart of the Wilds to immediately tap for a massive influx of mana based on your biggest creature. Umbral Collar Zealot provides the necessary outlet to bin your pieces while smoothing your draws through surveil, feeding the exact fodder required for Slimefoot and Squee's resurrection ability. With every loop, Slimefoot and Squee replaces the sacrificed material by spawning a fresh Saproling token, ensuring you have an endless supply of fuel to repeat the cycle indefinitely.