Sol Ring Sorry to be such a normie, but we're putting Sol Ring in first
Add Arcane Lighthouse if you're facing hexproof nuisances (Narset, Enlightened Master), Strip Mine to deal with pesky lands (Cabal Coffers), and whatever else you need
Nim Deathmantle works with Ashnod's Altar and a creature that creates a token when it enters the battlefield or dies to produce an infinite loop of deaths and enter the battlefield triggers
Best Saproling/Thallid Payoffs While the Thallids themselves usually include an outlet for the mountain of Saprolings you create, there are a few non-fungi cards that make great additions to a Saprolings deck
The Ardenvale Fealty makes a 2/2 Knight with vigilance instantly
II, III - Until your next turn, creatures can't attack you unless their controller pays for each of those creatures