Putrefy

Destroy target artifact or creature. It can't be regenerated.

Overrun

Creatures you control get +3/+3 and gain trample until end of turn. (Each of those creatures can deal excess combat damage to the player or planeswalker it's attacking.)

Slimefoot, the Stowaway

Whenever a Saproling you control dies, Slimefoot, the Stowaway deals 1 damage to each opponent and you gain 1 life.
{4}: Create a 1/1 green Saproling creature token.

Swamp

Yavimaya Sapherd

When Yavimaya Sapherd enters, create a 1/1 green Saproling creature token.

Deathbloom Thallid

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

Thallid Omnivore

{1}, Sacrifice another creature: Thallid Omnivore gets +2/+2 until end of turn. If a Saproling was sacrificed this way, you gain 2 life.

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.

Song of Freyalise

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Until your next turn, creatures you control gain "{T}: Add one mana of any color."
III — Put a +1/+1 counter on each creature you control. Those creatures gain vigilance, trample, and indestructible until end of turn.

Spore Swarm

Create three 1/1 green Saproling creature tokens.

Spontaneous Generation

Create a 1/1 green Saproling creature token for each card in your hand.

Jungle Hollow

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {B} or {G}.

Scatter the Seeds

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.)
Create three 1/1 green Saproling creature tokens.