Bolas's Citadel

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

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.

Jaheira, Friend of the Forest

Tokens you control have "{T}: Add {G}."
Choose a Background (You can have a Background as a second commander.)

Thelon of Havenwood

Each Fungus creature gets +1/+1 for each spore counter on it.
{B}{G}, Exile a Fungus card from a graveyard: Put a spore counter on each Fungus on the battlefield.

The Weatherseed Treaty

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)
I — Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
II — Create a 1/1 green Saproling creature token.
III — Domain — Target creature you control gets +X/+X and gains trample until end of turn, where X is the number of basic land types among lands you control.

Zulaport Cutthroat

Whenever Zulaport Cutthroat or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Eaten Alive

As an additional cost to cast this spell, sacrifice a creature or pay {3}{B}.
Exile target creature or planeswalker.

Path of Ancestry

Path of Ancestry enters the battlefield tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Sporesower Thallid

At the beginning of your upkeep, put a spore counter on each Fungus you control.
Remove three spore counters from Sporesower Thallid: Create a 1/1 green Saproling creature token.

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.

Thallid Shell-Dweller

Defender
At the beginning of your upkeep, put a spore counter on Thallid Shell-Dweller.
Remove three spore counters from Thallid Shell-Dweller: Create a 1/1 green Saproling creature token.

Nemata, Primeval Warden

Reach
If a creature an opponent controls would die, exile it instead. When you do, create a 1/1 green Saproling creature token.
{G}, Sacrifice a Saproling: Nemata, Primeval Warden gets +2/+2 until end of turn.
{1}{B}, Sacrifice two Saprolings: Draw a card.

Overrun

Creatures you control get +3/+3 and gain trample until end of turn.

Golgari Charm

Choose one —
• All creatures get -1/-1 until end of turn.
• Destroy target enchantment.
• Regenerate each creature you control.

Casualties of War

Choose one or more —
• Destroy target artifact.
• Destroy target creature.
• Destroy target enchantment.
• Destroy target land.
• Destroy target planeswalker.

Tukatongue Thallid

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

Vindictive Vampire

Whenever another creature you control dies, Vindictive Vampire deals 1 damage to each opponent and you gain 1 life.

Sporeweb Weaver

Reach, hexproof from blue
Whenever Sporeweb Weaver is dealt damage, you gain 1 life and create a 1/1 green Saproling creature token.

Fungal Rebirth

Return target permanent card from your graveyard to your hand. If a creature died this turn, create two 1/1 green Saproling creature tokens.

Utopia Mycon

At the beginning of your upkeep, put a spore counter on Utopia Mycon.
Remove three spore counters from Utopia Mycon: Create a 1/1 green Saproling creature token.
Sacrifice a Saproling: Add one mana of any color.

Sporemound

Landfall — Whenever a land enters the battlefield under your control, create a 1/1 green Saproling creature token.

Tear Asunder

Kicker {1}{B} (You may pay an additional {1}{B} as you cast this spell.)
Exile target artifact or enchantment. If this spell was kicked, exile target nonland permanent instead.

Thallid Soothsayer

Primal Growth

Kicker—Sacrifice a creature. (You may sacrifice a creature in addition to any other costs as you cast this spell.)
Search your library for a basic land card, put that card onto the battlefield, then shuffle. If this spell was kicked, instead search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Sporecrown Thallid

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

Sprout Swarm

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.)
Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)
Create a 1/1 green Saproling creature token.

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.

Spore Flower

At the beginning of your upkeep, put a spore counter on Spore Flower.
Remove three spore counters from Spore Flower: Prevent all combat damage that would be dealt this turn.

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.

Yavimaya Sapherd

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

Winding Constrictor

If one or more counters would be put on an artifact or creature you control, that many plus one of each of those kinds of counters are put on that permanent instead.
If you would get one or more counters, you get that many plus one of each of those kinds of counters instead.

Hissing Quagmire

Hissing Quagmire enters the battlefield tapped.
{T}: Add {B} or {G}.
{1}{B}{G}: Hissing Quagmire becomes a 2/2 black and green Elemental creature with deathtouch until end of turn. It's still a land.

Deathspore Thallid

At the beginning of your upkeep, put a spore counter on Deathspore Thallid.
Remove three spore counters from Deathspore Thallid: Create a 1/1 green Saproling creature token.
Sacrifice a Saproling: Target creature gets -1/-1 until end of turn.

Thallid

At the beginning of your upkeep, put a spore counter on Thallid.
Remove three spore counters from Thallid: Create a 1/1 green Saproling creature token.

Culling Ritual

Destroy each nonland permanent with mana value 2 or less. Add {B} or {G} for each permanent destroyed this way.

Sylvan Anthem

Green creatures you control get +1/+1.
Whenever a green creature enters the battlefield under your control, scry 1.

Swamp

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Sporoloth Ancient

At the beginning of your upkeep, put a spore counter on Sporoloth Ancient.
Creatures you control have "Remove two spore counters from this creature: Create a 1/1 green Saproling creature token."

Mortality Spear

This spell costs {2} less to cast if you gained life this turn.
Destroy target nonland permanent.

Binding the Old Gods

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Destroy target nonland permanent an opponent controls.
II — Search your library for a Forest card, put it onto the battlefield tapped, then shuffle.
III — Creatures you control gain deathtouch until end of turn.

Forest

Morbid Bloom

Exile target creature card from a graveyard, then create X 1/1 green Saproling creature tokens, where X is the exiled card's toughness.

Haunted Mire

({T}: Add {B} or {G}.)
Haunted Mire enters the battlefield tapped.

Smothering Abomination

Devoid (This card has no color.)
Flying
At the beginning of your upkeep, sacrifice a creature.
Whenever you sacrifice a creature, draw a card.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Spore Crawler

Dina, Soul Steeper

Whenever you gain life, each opponent loses 1 life.
{1}, Sacrifice another creature: Dina, Soul Steeper gets +X/+0 until end of turn, where X is the sacrificed creature's power.

Plaguemaw Beast

{T}, Sacrifice a creature: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Putrefy

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

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

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.

Mycoloth

Devour 2 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with twice that many +1/+1 counters on it.)
At the beginning of your upkeep, create a 1/1 green Saproling creature token for each +1/+1 counter on Mycoloth.

Golgari Rot Farm

Golgari Rot Farm enters the battlefield tapped.
When Golgari Rot Farm enters the battlefield, return a land you control to its owner's hand.
{T}: Add {B}{G}.

Verdeloth the Ancient

Kicker {X} (You may pay an additional {X} as you cast this spell.)
Saproling creatures and other Treefolk creatures get +1/+1.
When Verdeloth the Ancient enters the battlefield, if it was kicked, create X 1/1 green Saproling creature tokens.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Altar's Reap

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Trudge Garden

Whenever you gain life, you may pay {2}. If you do, create a 4/4 green Fungus Beast creature token with trample.

Thelonite Hermit

All Saprolings get +1/+1.
Morph {3}{G}{G} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Thelonite Hermit is turned face up, create four 1/1 green Saproling creature tokens.

Undercellar Myconid

Whenever Undercellar Myconid enters the battlefield or dies, create a 1/1 green Saproling creature token.
{T}: Add one mana of any color.

Sol Ring

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Arcane Signet

Butcher of Malakir

Flying
Whenever Butcher of Malakir or another creature you control dies, each opponent sacrifices a creature.

Vraska, Golgari Queen

+2: You may sacrifice another permanent. If you do, you gain 1 life and draw a card.
−3: Destroy target nonland permanent with mana value 3 or less.
−9: You get an emblem with "Whenever a creature you control deals combat damage to a player, that player loses the game."

Read the Bones

Scry 2, then draw two cards. You lose 2 life.

Grim Backwoods

{T}: Add {C}.
{2}{B}{G}, {T}, Sacrifice a creature: Draw a card.

Evolutionary Leap

{G}, Sacrifice a creature: Reveal cards from the top of your library until you reveal a creature card. Put that card into your hand and the rest on the bottom of your library in a random order.

Verdant Force

At the beginning of each upkeep, create a 1/1 green Saproling creature token.

Rot Shambler

Whenever another creature you control dies, put a +1/+1 counter on Rot Shambler.