Ferrafor, Young Yew gives you a substantial burst of saprolings, and you don't need to be the player with the most counters among creatures for this to be incredible
If youre playing a higher Bracket deck, this one could be sweet in Edgar Markov, Kaalia, Krrik, Son of Yawgmoth, or even The Ur-Dragon
Dakkon, Shadow Slayer Dakkon, Shadow Slayer is a great callback to one of the most iconic oldschool cards, Dakkon Blackblade, fittingly drawn again by the legendary RKF
This is a great little list with everything you'll need to get started with spirits as a deck, but I also want to present a bit of a different take and upgrade it in the process, as I'm wont to do
Abzan Beastmaster Aerie Bowmasters Ainok Artillerist Ainok Guide Ainok Survivalist Ainok Wayfarer Arbor Adherent B-I-N-G-O Bayou Groff Burnished Dunestomper District Mascot Dogmeat, Ever Loyal Eel-Hounds Elven Warhounds Faithful Watchdog Greater Mossdog Greater Tanuki Hydradoodle Karvanista, Loyal Lupari Longshot Squad Lucky the Pizza Dog Mongrel Pack Mossdog Mowu, Loyal Companion Mushroom Watchdogs Pako, Arcane Retriever Pet Avengers Rin and Seri, Inseparable Salt Road Ambushers Sandsteppe Scavenger Tanuki Transplanter Thrashing Mossdog Trade Route Envoy Traveling Botanist Wary Watchdog Wild Dogs Wild Mongrel
Designer Notes: Swarm the board with tokens, then play your commander to overwhelm your opponents and remove their smaller creatures