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.

People of the Woods

People of the Woods's toughness is equal to the number of Forests you control.

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}

Battlewand Oak

Whenever a Forest you control enters, Battlewand Oak gets +2/+2 until end of turn.
Whenever you cast a Treefolk spell, Battlewand Oak gets +2/+2 until end of turn.

Nessian Game Warden

When Nessian Game Warden enters, look at the top X cards of your library, where X is the number of Forests you control. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Argothian Elder

Thelonite Druid

{1}{G}, {T}, Sacrifice a creature: Forests you control become 2/3 creatures until end of turn. They're still lands.

Gaea's Cradle

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

Crash Landing

Target creature with flying loses flying until end of turn. Crash Landing deals damage to that creature equal to the number of Forests you control.

Gaea's Revenge

This spell can't be countered.
Haste
Gaea's Revenge can't be the target of nongreen spells or abilities from nongreen sources.

Timber Protector

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

Cradle Guard

Trample
Echo {1}{G}{G} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)

Titania, Gaea Incarnate

Vigilance, reach, trample, haste
Titania, Gaea Incarnate'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.

Cloudcrown Oak

Reach (This creature can block creatures with flying.)

Argothian Pixies

Argothian Pixies can't be blocked by artifact creatures.
Prevent all damage that would be dealt to Argothian Pixies by artifact creatures.

Blanchwood Treefolk

Argothian Treefolk

Prevent all damage that would be dealt to Argothian Treefolk by artifact sources.

Argoth, Sanctum of Nature

Argoth, Sanctum of Nature 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.)

Dungrove Elder

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
Dungrove Elder's power and toughness are each equal to the number of Forests you control.

Kalonian Twingrove

Kalonian Twingrove's power and toughness are each equal to the number of Forests you control.
When Kalonian Twingrove enters, create a green Treefolk Warrior creature token with "This creature's power and toughness are each equal to the number of Forests you control."

Gaea's Herald

Gaea's Touch

{0}: You may put a basic Forest card from your hand onto the battlefield. Activate only as a sorcery and only once each turn.
Sacrifice Gaea's Touch: Add {G}{G}.

Gaea's Courser

Whenever Gaea's Courser attacks, if there are three or more creature cards in your graveyard, draw a card.

Treefolk Seedlings

Treefolk Seedlings's toughness is equal to the number of Forests you control.

Gaea's Bounty

Search your library for up to two Forest cards, reveal those cards, put them into your hand, then shuffle.

Ambush Commander

Forests you control are 1/1 green Elf creatures that are still lands.
{1}{G}, Sacrifice an Elf: Target creature gets +3/+3 until end of turn.

Uktabi Wildcats

Uktabi Wildcats's power and toughness are each equal to the number of Forests you control.
{G}, Sacrifice a Forest: Regenerate Uktabi Wildcats.

Gaea's Avenger

Gaea's Avenger's power and toughness are each equal to 1 plus the number of artifacts your opponents control.

Gaea's Liege

As long as Gaea's Liege isn't attacking, its power and toughness are each equal to the number of Forests you control. As long as Gaea's Liege is attacking, its power and toughness are each equal to the number of Forests defending player controls.
{T}: Target land becomes a Forest until Gaea's Liege leaves the battlefield.

Ambassador Oak

When Ambassador Oak enters, create a 1/1 green Elf Warrior creature token.

Gaea's Gift

Put a +1/+1 counter on target creature you control. It gains reach, trample, hexproof, and indestructible until end of turn. (It can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)

Bull Elephant

When Bull Elephant enters, sacrifice it unless you return two Forests you control to their owner's hand.

Aspect of Wolf

Enchant creature
Enchanted creature gets +X/+Y, where X is half the number of Forests you control, rounded down, and Y is half the number of Forests you control, rounded up.

Mirkwood Channeler

At the beginning of combat on your turn, target Elf you control gains trample and gets +X/+X until end of turn, where X is the number of Forests you control.

Crabapple Cohort

Crabapple Cohort gets +1/+1 as long as you control another green creature.

Titania, Protector of Argoth

When Titania, Protector of Argoth 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.

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, Eyes of Gaea and untap it.

Ashaya, Soul of the Wild

Ashaya, Soul of the Wild's power and toughness are each equal to the number of lands you control.
Nontoken creatures you control are Forest lands in addition to their other types. (They're still affected by summoning sickness.)

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.
Dauntless Dourbark has trample as long as you control another Treefolk.

Woodland Guidance

Return target card from your graveyard to your hand. Clash with an opponent. If you win, untap all Forests you control. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)
Exile Woodland Guidance.