Sporecrown Thallid

Each other creature you control that's a Fungus or Saproling gets +1/+1.

Spore Crawler

Shroofus Sproutsire

Trample
Whenever a Saproling you control deals combat damage to a player, create that many 1/1 green Saproling creature tokens.

Might of the Masses

Target creature gets +1/+1 until end of turn for each creature you control.

Band Together

Up to two target creatures you control each deal damage equal to their power to another target creature.

Saproling Migration

Kicker {4} (You may pay an additional {4} as you cast this spell.)
Create two 1/1 green Saproling creature tokens. If this spell was kicked, create four of those tokens instead.

Saurian Symbiote

Reach (This creature can block creatures with flying.)
When Saurian Symbiote enters, choose one —
• Put a +1/+1 counter on Saurian Symbiote.
• Create a 1/1 green Saproling creature token.

Thriving Grove

Thriving Grove enters tapped. As it enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

Tukatongue Thallid

When Tukatongue Thallid dies, create a 1/1 green Saproling creature token.

Overwhelm

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Creatures you control get +3/+3 until end of turn.

Forest

Spore Swarm

Create three 1/1 green Saproling creature tokens.

Slimy Piper

Whenever Slimy Piper attacks, it gets +1/+1 until end of turn. If you control four or more creatures, it gets +2/+2 and gains indestructible until end of turn instead. (Damage and effects that say "destroy" don't destroy it.)

Fungal Plots

{1}{G}, Exile a creature card from your graveyard: Create a 1/1 green Saproling creature token.
Sacrifice two Saprolings: You gain 2 life and draw a card.