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.

Scute Swarm

Landfall — Whenever a land you control enters, create a 1/1 green Insect creature token. If you control six or more lands, create a token that's a copy of Scute Swarm instead.

Forest

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Kodama's Reach

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.

Cultivate

Sylvan Scrying

Search your library for a land card, reveal it, put it into your hand, then shuffle.

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.)

Lotus Cobra

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

Avenger of Zendikar

When Avenger of Zendikar 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.

Azusa, Lost but Seeking

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

Windfall

Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Roil Elemental

Flying
Landfall — Whenever a land you control enters, you may gain control of target creature for as long as you control Roil Elemental.

Spelunking

When Spelunking enters, draw a card, then you may put a land card from your hand onto the battlefield. If you put a Cave onto the battlefield this way, you gain 4 life.
Lands you control enter untapped.

Constant Mists

Buyback—Sacrifice a land. (You may sacrifice a land in addition to any other costs as you cast this spell. If you do, put this card into your hand as it resolves.)
Prevent all combat damage that would be dealt this turn.

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Shifting Woodland

Shifting Woodland enters tapped unless you control a Forest.
{T}: Add {G}.
Delirium — {2}{G}{G}: Shifting Woodland becomes a copy of target permanent card in your graveyard until end of turn. Activate only if there are four or more card types among cards in your graveyard.

Entish Restoration

Sacrifice a land. Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle. If you control a creature with power 4 or greater, instead search your library for up to three basic land cards, put them onto the battlefield tapped, then shuffle.

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.)

Counterspell

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Misty Rainforest

{T}, Pay 1 life, Sacrifice Misty Rainforest: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

Hermit Druid

{G}, {T}: Reveal cards from the top of your library until you reveal a basic land card. Put that card into your hand and all other cards revealed this way into your graveyard.

Shriekmaw

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
When Shriekmaw enters, destroy target nonartifact, nonblack creature.
Evoke {1}{B} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

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.

Case of the Locked Hothouse

You may play an additional land on each of your turns.
To solve — You control seven or more lands. (If unsolved, solve at the beginning of your end step.)
Solved — You may look at the top card of your library any time, and you may play lands and cast creature and enchantment spells from the top of your library.

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Golgari Signet

Ashiok, Dream Render

Spells and abilities your opponents control can't cause their controller to search their library.
−1: Target player mills four cards. Then exile each opponent's graveyard.

Dryad of the Ilysian Grove

You may play an additional land on each of your turns.
Lands you control are every basic land type in addition to their other types.

Birds of Paradise

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.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Boseiju, Who Endures

{T}: Add {G}.
Channel — {1}{G}, Discard Boseiju, Who Endures: Destroy target artifact, enchantment, or nonbasic land an opponent controls. That player may search their library for a land card with a basic land type, put it onto the battlefield, then shuffle. This ability costs {1} less to activate for each legendary creature you control.

Cultivator Colossus

Trample
Cultivator Colossus's power and toughness are each equal to the number of lands you control.
When Cultivator Colossus enters, you may put a land card from your hand onto the battlefield tapped. If you do, draw a card and repeat this process.

Spore Frog

Sacrifice Spore Frog: Prevent all combat damage that would be dealt this turn.

Exploration

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

Sakura-Tribe Elder

Sacrifice Sakura-Tribe Elder: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Verdant Catacombs

{T}, Pay 1 life, Sacrifice Verdant Catacombs: Search your library for a Swamp or Forest card, put it onto the battlefield, then shuffle.

Scapeshift

Sacrifice any number of lands. Search your library for up to that many land cards, put them onto the battlefield tapped, then shuffle.

Island

Simic Signet

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Ob Nixilis, the Fallen

Landfall — Whenever a land you control enters, you may have target player lose 3 life. If you do, put three +1/+1 counters on Ob Nixilis, the Fallen.

Watery Grave

({T}: Add {U} or {B}.)
As Watery Grave enters, you may pay 2 life. If you don't, it enters tapped.

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Arcane Signet

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

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Zagoth Triome

({T}: Add {B}, {G}, or {U}.)
Zagoth Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Iridescent Vinelasher

Offspring {2} (You may pay an additional {2} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Landfall — Whenever a land you control enters, this creature deals 1 damage to target opponent.

Siren Stormtamer

Flying
{U}, Sacrifice Siren Stormtamer: Counter target spell or ability that targets you or a creature you control.

Conduit of Worlds

You may play lands from your graveyard.
{T}: Choose target nonland permanent card in your graveyard. If you haven't cast a spell this turn, you may cast that card. If you do, you can't cast additional spells this turn. Activate only as a sorcery.

Explore

You may play an additional land this turn.
Draw a card.

Glacial Chasm

Cumulative upkeep—Pay 2 life. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
When Glacial Chasm enters, sacrifice a land.
Creatures you control can't attack.
Prevent all damage that would be dealt to you.

Rampaging Baloths

Trample
Landfall — Whenever a land you control enters, you may create a 4/4 green Beast creature token.

Dark Ritual

Maze of Ith

{T}: Untap target attacking creature. Prevent all combat damage that would be dealt to and dealt by that creature this turn.

Oracle of Mul Daya

You may play an additional land on each of your turns.
Play with the top card of your library revealed.
You may play lands from the top of your library.

Swamp

Braids, Arisen Nightmare

At the beginning of your end step, you may sacrifice an artifact, creature, enchantment, land, or planeswalker. If you do, each opponent may sacrifice a permanent of their choice that shares a card type with it. For each opponent who doesn't, that player loses 2 life and you draw a card.

Foreboding Landscape

{T}: Add {C}.
{T}, Sacrifice Foreboding Landscape: Search your library for a basic Swamp, Forest, or Island card, put it onto the battlefield tapped, then shuffle.
Cycling {B}{G}{U} ({B}{G}{U}, Discard this card: Draw a card.)

Doc Aurlock, Grizzled Genius

Spells you cast from your graveyard or from exile cost {2} less to cast.
Plotting cards from your hand costs {2} less.

Tatyova, Benthic Druid

Landfall — Whenever a land you control enters, you gain 1 life and draw a card.

Krosan Grip

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Destroy target artifact or enchantment.

Muldrotha, the Gravetide

During each of your turns, you may play a land and cast a permanent spell of each permanent type from your graveyard. (If a card has multiple permanent types, choose one as you play it.)

Field of the Dead

Field of the Dead enters tapped.
{T}: Add {C}.
Whenever Field of the Dead or another land you control enters, if you control seven or more lands with different names, create a 2/2 black Zombie creature token.

Baleful Strix

Flying, deathtouch
When Baleful Strix enters, draw a card.

Prismatic Vista

{T}, Pay 1 life, Sacrifice Prismatic Vista: Search your library for a basic land card, put it onto the battlefield, then shuffle.

Uro, Titan of Nature's Wrath

When Uro enters, sacrifice it unless it escaped.
Whenever Uro enters or attacks, you gain 3 life and draw a card, then you may put a land card from your hand onto the battlefield.
Escape—{G}{G}{U}{U}, Exile five other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Aesi, Tyrant of Gyre Strait

You may play an additional land on each of your turns.
Landfall — Whenever a land you control enters, you may draw a card.

Phyrexian Tower

{T}: Add {C}.
{T}, Sacrifice a creature: Add {B}{B}.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

The Gitrog Monster

Deathtouch
At the beginning of your upkeep, sacrifice The Gitrog Monster unless you sacrifice a land.
You may play an additional land on each of your turns.
Whenever one or more land cards are put into your graveyard from anywhere, draw a card.

Sylvan Safekeeper

Sacrifice a land: Target creature you control gains shroud until end of turn. (It can't be the target of spells or abilities.)

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.