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 loop turns the graveyard into a bustling engine by leveraging Selvala, Heart of the Wilds to generate a massive influx of mana whenever creatures return to the board. You can feed your own creatures to Umbral Collar Zealot to filter your draws and set up the graveyard, putting both Selvala and Slimefoot and Squee right where you want them. Once they are there, Slimefoot and Squee uses that gathered mana and a fresh Saproling token to resurrect the entire pair back to the battlefield. The ensuing arrival automatically spawns a brand new Saproling to sustain the cycle, while Dragonlord Kolaghan stands ready in the background to complete the legendary synergy of the command zone.