Staff of Titania

Equipped creature gets +X/+X, where X is the number of Forests you control.
Whenever equipped creature attacks, create a 1/1 green Forest Dryad land creature token. (It's affected by summoning sickness.)
Equip {3}

Yavimaya, Cradle of Growth

Each land is a Forest in addition to its other land types.

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Titania's Command

Choose two —
• Exile target player's graveyard. You gain 1 life for each card exiled this way.
• Search your library for up to two land cards, put them onto the battlefield tapped, then shuffle.
• Create two 2/2 green Bear creature tokens.
• Put two +1/+1 counters on each creature you control.

Castle Garenbrig

This land enters tapped unless you control a Forest.
{T}: Add {G}.
{2}{G}{G}, {T}: Add six {G}. Spend this mana only to cast creature spells or activate abilities of creatures.

Zendikar's Roil

Landfall — Whenever a land you control enters, create a 2/2 green Elemental creature token.

Colossal Majesty

At the beginning of your upkeep, if you control a creature with power 4 or greater, draw a card.

Willow Geist

Trample
Whenever one or more cards leave your graveyard, put a +1/+1 counter on this creature.
When this creature dies, you gain life equal to its power.

Concordant Crossroads

Reach of Branches

Create a 2/5 green Treefolk Shaman creature token.
Whenever a Forest you control enters, you may return this card from your graveyard to your hand.

Sapseep Forest

({T}: Add {G}.)
This land enters tapped.
{G}, {T}: You gain 1 life. Activate only if you control two or more green permanents.

Kazandu Valley

Kazandu Mammoth

Landfall — Whenever a land you control enters, this creature gets +2/+2 until end of turn.

Kazandu Mammoth // Kazandu Valley

Wrenn and Seven

+1: Reveal the top four cards of your library. Put all land cards revealed this way into your hand and the rest into your graveyard.
0: Put any number of land cards from your hand onto the battlefield tapped.
−3: Create a green Treefolk creature token with reach and "This token's power and toughness are each equal to the number of lands you control."
−8: Return all permanent cards from your graveyard to your hand. You get an emblem with "You have no maximum hand size."

Titania, Gaea Incarnate

Vigilance, reach, trample, haste
Titania's power and toughness are each equal to the number of lands you control.
When Titania enters, return all land cards from your graveyard to the battlefield tapped.
{3}{G}: Put four +1/+1 counters on target land you control. It becomes a 0/0 Elemental creature with haste. It's still a land.

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Lotus Cobra

Landfall — Whenever a land you control enters, add one mana of any color.

Elemental Bond

Whenever a creature you control with power 3 or greater enters, draw a card.

Argoth, Sanctum of Nature

This land enters tapped unless you control a legendary green creature.
{T}: Add {G}.
{2}{G}{G}, {T}: Create a 2/2 green Bear creature token, then mill three cards. Activate only as a sorcery.
(Melds with Titania, Voice of Gaea.)

Garruk, Primal Hunter

+1: Create a 3/3 green Beast creature token.
−3: Draw cards equal to the greatest power among creatures you control.
−6: Create a 6/6 green Wurm creature token for each land you control.

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.

Exploration

You may play an additional land on each of your turns.

Avenger of Zendikar

When this creature enters, create a 0/1 green Plant creature token for each land you control.
Landfall — Whenever a land you control enters, you may put a +1/+1 counter on each Plant creature you control.

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Springbloom Druid

When this creature enters, you may sacrifice a land. If you do, search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Druid Class

(Gain the next level as a sorcery to add its ability.)
Landfall — Whenever a land you control enters, you gain 1 life.
{2}{G}: Level 2
You may play an additional land on each of your turns.
{4}{G}: Level 3
When this Class becomes level 3, target land you control becomes a creature with haste and "This creature's power and toughness are each equal to the number of lands you control." It's still a land.

Seedguide Ash

When this creature dies, you may search your library for up to three Forest cards, put them onto the battlefield tapped, then shuffle.

Azusa, Lost but Seeking

You may play two additional lands on each of your turns.

Awaken the Woods

Create X 1/1 green Forest Dryad land creature tokens. (They're affected by summoning sickness.)

Gwenna, Eyes of Gaea

{T}: Add two mana in any combination of colors. Spend this mana only to cast creature spells or activate abilities of creature sources.
Whenever you cast a creature spell with power 5 or greater, put a +1/+1 counter on Gwenna and untap it.

Return of the Wildspeaker

Choose one —
• Draw cards equal to the greatest power among non-Human creatures you control.
• Non-Human creatures you control get +3/+3 until end of turn.

Sol Ring

Dauntless Dourbark

Dauntless Dourbark's power and toughness are each equal to the number of Forests you control plus the number of Treefolk you control.
This creature has trample as long as you control another Treefolk.

Vinelasher Kudzu

Landfall — Whenever a land you control enters, put a +1/+1 counter on this creature.

Titania, Nature's Force

You may play Forests from your graveyard.
Whenever a Forest you control enters, create a 5/3 green Elemental creature token.
Whenever an Elemental you control dies, you may mill three cards.

Gingerbread Cabin

({T}: Add {G}.)
This land enters tapped unless you control three or more other Forests.
When this land enters untapped, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")

Harrow

As an additional cost to cast this spell, sacrifice a land.
Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Crop Rotation

As an additional cost to cast this spell, sacrifice a land.
Search your library for a land card, put that card onto the battlefield, then shuffle.

Elvish Reclaimer

This creature gets +2/+2 as long as there are three or more land cards in your graveyard.
{2}, {T}, Sacrifice a land: Search your library for a land card, put it onto the battlefield tapped, then shuffle.

Rootpath Purifier

Lands you control and land cards in your library are basic.

Jaheira's Respite

Search your library for up to X basic land cards, where X is the number of creatures attacking you, put those cards onto the battlefield tapped, then shuffle.
Prevent all combat damage that would be dealt this turn.

Beastmaster Ascension

Whenever a creature you control attacks, you may put a quest counter on this enchantment.
As long as this enchantment has seven or more quest counters on it, creatures you control get +5/+5.

Garruk's Uprising

When this enchantment enters, if you control a creature with power 4 or greater, draw a card.
Creatures you control have trample. (Each of those creatures can deal excess combat damage to the player or planeswalker it's attacking.)
Whenever a creature you control with power 4 or greater enters, draw a card.

World Shaper

Whenever this creature attacks, you may mill three cards.
When this creature dies, return all land cards from your graveyard to the battlefield tapped.

Harmonize

Lotus Field

Hexproof
This land enters tapped.
When this land enters, sacrifice two lands.
{T}: Add three mana of any one color.

Forest

Yedora, Grave Gardener

Whenever another nontoken creature you control dies, you may return it to the battlefield face down under its owner's control. It's a Forest land. (It has no other types or abilities.)

Blanchwood Armor

Enchant creature
Enchanted creature gets +1/+1 for each Forest you control.

Snow-Covered Forest

Momentous Fall

As an additional cost to cast this spell, sacrifice a creature.
You draw cards equal to the sacrificed creature's power, then you gain life equal to its toughness.

Rishkar's Expertise

Draw cards equal to the greatest power among creatures you control.
You may cast a spell with mana value 5 or less from your hand without paying its mana cost.

Rampant Growth

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

Gaea's Cradle

{T}: Add {G} for each creature you control.

Unnatural Growth

At the beginning of each combat, double the power and toughness of each creature you control until end of turn.

Roiling Regrowth

Sacrifice a land. Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Boseiju, Who Shelters All

Boseiju enters tapped.
{T}, Pay 2 life: Add {C}. If that mana is spent on an instant or sorcery spell, that spell can't be countered.

Ulvenwald Observer

Whenever a creature you control with toughness 4 or greater dies, draw a card.

Seer's Sundial

Landfall — Whenever a land you control enters, you may pay {2}. If you do, draw a card.

Explorer's Scope

Whenever equipped creature attacks, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Life's Legacy

As an additional cost to cast this spell, sacrifice a creature.
Draw cards equal to the sacrificed creature's power.

Titania, Protector of Argoth

When Titania enters, return target land card from your graveyard to the battlefield.
Whenever a land you control is put into a graveyard from the battlefield, create a 5/3 green Elemental creature token.

Tempt with Discovery

Tempting offer — Search your library for a land card and put it onto the battlefield. Each opponent may search their library for a land card and put it onto the battlefield. For each opponent who searches a library this way, search your library for a land card and put it onto the battlefield. Then each player who searched a library this way shuffles.

Fertile Thicket

This land enters tapped.
When this land enters, you may look at the top five cards of your library. If you do, reveal up to one basic land card from among them, then put that card on top of your library and the rest on the bottom in any order.
{T}: Add {G}.

Jaheira, Friend of the Forest

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

Oran-Rief, the Vastwood

This land enters tapped.
{T}: Add {G}.
{T}: Put a +1/+1 counter on each green creature that entered this turn.

Greensleeves, Maro-Sorcerer

Protection from planeswalkers and from Wizards
Greensleeves's power and toughness are each equal to the number of lands you control.
Landfall — Whenever a land you control enters, create a 3/3 green Badger creature token.

Splendid Reclamation

Return all land cards from your graveyard to the battlefield tapped.

Hollow Trees

This land enters tapped.
You may choose not to untap this land during your untap step.
At the beginning of your upkeep, if this land is tapped, put a storage counter on it.
{T}, Remove any number of storage counters from this land: Add {G} for each storage counter removed this way.

Ancient Greenwarden

Reach (This creature can block creatures with flying.)
You may play lands from your graveyard.
If a land entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Wayward Swordtooth

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
You may play an additional land on each of your turns.
This creature can't attack or block unless you have the city's blessing.

Treefolk Harbinger

When this creature enters, you may search your library for a Treefolk or Forest card, reveal it, then shuffle and put that card on top.

The Mending of Dominaria

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Mill two cards, then you may return a creature card from your graveyard to your hand.
III — Return all land cards from your graveyard to the battlefield, then shuffle your graveyard into your library.

Timber Protector

Other Treefolk creatures you control get +1/+1.
Other Treefolk and Forests you control have indestructible.

Summer Bloom

You may play up to three additional lands this turn.

Titania, Voice of Gaea

Reach
Whenever one or more land cards are put into your graveyard from anywhere, you gain 2 life.
At the beginning of your upkeep, if there are four or more land cards in your graveyard and you both own and control Titania, Voice of Gaea and a land named Argoth, Sanctum of Nature, exile them, then meld them into Titania, Gaea Incarnate.