Explore the Underdark

Search your library for up to two basic land cards and/or Gate cards, put them onto the battlefield tapped, then shuffle.
You take the initiative.

Yavimaya, Cradle of Growth

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

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.

Island

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.

Joint Exploration

Kicker {G} (You may pay an additional {G} as you cast this spell.)
Scry 2, then draw a card. If this spell was kicked, you may put a land card from your hand onto the battlefield.

Retreat to Coralhelm

Landfall — Whenever a land you control enters, choose one —
• You may tap or untap target creature.
• Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

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.

Damnation

Destroy all creatures. They can't be regenerated.

Way of the Thief

Enchant creature
Enchanted creature gets +2/+2.
Enchanted creature can't be blocked as long as you control a Gate.

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.

Zimone, Quandrix Prodigy

{1}, {T}: You may put a land card from your hand onto the battlefield tapped.
{4}, {T}: Draw a card. If you control eight or more lands, draw two cards instead.

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.

Maze's End

This land enters tapped.
{T}: Add {C}.
{3}, {T}, Return this land to its owner's hand: Search your library for a Gate card, put it onto the battlefield, then shuffle. If you control ten or more Gates with different names, you win the game.

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.

Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

Villainous Wealth

Target opponent exiles the top X cards of their library. You may cast any number of spells with mana value X or less from among them without paying their mana costs.

Ulvenwald Hydra

Reach
Ulvenwald Hydra's power and toughness are each equal to the number of lands you control.
When Ulvenwald Hydra enters, you may search your library for a land card, put it onto the battlefield tapped, then shuffle.

Greensleeves, Maro-Sorcerer

Protection from planeswalkers and from Wizards
Greensleeves, Maro-Sorcerer'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.

Tatyova, Benthic Druid

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

Black Dragon Gate

Black Dragon Gate enters tapped.
As Black Dragon Gate enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Expedition Map

{2}, {T}, Sacrifice this artifact: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Eureka Moment

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

Reliquary Tower

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

Kura, the Boundless Sky

Flying, deathtouch
When Kura, the Boundless Sky dies, choose one —
• Search your library for up to three land cards, reveal them, put them into your hand, then shuffle.
• Create an X/X green Spirit creature token, where X is the number of lands you control.

Emergent Ultimatum

Search your library for up to three monocolored cards with different names and exile them. An opponent chooses one of those cards. Shuffle that card into your library. You may cast the other cards without paying their mana costs. Exile Emergent Ultimatum.

Archelos, Lagoon Mystic

As long as Archelos, Lagoon Mystic is tapped, other permanents enter tapped.
As long as Archelos is untapped, other permanents enter untapped.

Heap Gate

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{1}, {T}, Tap an untapped Gate you control: Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Navigation Orb

{2}, {T}, Sacrifice Navigation Orb: Search your library for up to two basic land cards and/or Gate cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Forest

Winged Boots

Equipped creature has flying and ward {4}. (Whenever equipped creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {4}.)
Equip {1}

Augur of Autumn

You may look at the top card of your library any time.
You may play lands from the top of your library.
Coven — As long as you control three or more creatures with different powers, you may cast creature spells from the top of your library.

Simic Guildgate

This land enters tapped.
{T}: Add {G} or {U}.

Lotus Cobra

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

Swamp

Beast Within

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

Assassin's Trophy

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Crucible of Worlds

Wilderness Reclamation

At the beginning of your end step, untap all lands you control.

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.

Thespian's Stage

{T}: Add {C}.
{2}, {T}: Thespian's Stage becomes a copy of target land, except it has this ability.

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.)

Thran Portal

Thran Portal enters tapped unless you control two or fewer other lands.
As Thran Portal enters, choose a basic land type.
Thran Portal is the chosen type in addition to its other types.
Mana abilities of Thran Portal cost an additional 1 life to activate.

Academy Manufactor

If you would create a Clue, Food, or Treasure token, instead create one of each.

Golgari Guildgate

This land enters tapped.
{T}: Add {B} or {G}.

Mindbreak Trap

If an opponent cast three or more spells this turn, you may pay {0} rather than pay this spell's mana cost.
Exile any number of target spells.

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}

Ramunap Excavator

Sea Gate

Sea Gate enters tapped.
As Sea Gate enters, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

Circuitous Route

Search your library for up to two basic land cards and/or Gate cards, put them onto the battlefield tapped, then shuffle.

Baldur's Gate

{T}: Add {C}.
{2}, {T}: Add X mana of any one color, where X is the number of other Gates you control.

Rootpath Purifier

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

Plasm Capture

Counter target spell. At the beginning of your next first main phase, add X mana in any combination of colors, where X is that spell's mana value.

Guild Summit

When Guild Summit enters, you may tap any number of untapped Gates you control. Draw a card for each Gate tapped this way.
Whenever a Gate you control enters, draw a card.

Elvish Reclaimer

Elvish Reclaimer 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.

Basilisk Gate

{T}: Add {C}.
{2}, {T}: Target creature gets +X/+X until end of turn, where X is the number of Gates you control. Activate only as a sorcery.

District Guide

When District Guide enters, you may search your library for a basic land card or Gate card, reveal it, put it into your hand, then shuffle.

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.

Rampaging Baloths

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

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Manor Gate

Manor Gate enters tapped.
As Manor Gate enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

Open the Gates

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

Woodland Chasm

({T}: Add {B} or {G}.)
Woodland Chasm enters tapped.

Azusa, Lost but Seeking

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

Gateway Plaza

Gateway Plaza enters tapped.
When Gateway Plaza enters, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Gate Colossus

This spell costs {1} less to cast for each Gate you control.
This creature can't be blocked by creatures with power 2 or less.
Whenever a Gate you control enters, you may put this card from your graveyard on top of your library.

Tireless Provisioner

Landfall — Whenever a land you control enters, create a Food token or a Treasure token. (Food is an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life." Treasure is an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Demolition Field

{T}: Add {C}.
{2}, {T}, Sacrifice this land: Destroy target nonbasic land an opponent controls. That land's controller may search their library for a basic land card, put it onto the battlefield, then shuffle. You may search your library for a basic land card, put it onto the battlefield, then shuffle.

Vesuva

You may have Vesuva enter tapped as a copy of any land on the battlefield.

Awaken the Woods

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

Flood of Tears

Return all nonland permanents to their owners' hands. If you return four or more nontoken permanents you control this way, you may put a permanent card from your hand onto the battlefield.

Courser of Kruphix

Play with the top card of your library revealed.
You may play lands from the top of your library.
Landfall — Whenever a land you control enters, you gain 1 life.

Torment of Hailfire

Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent of their choice or discards a card.

Counterspell

Dimir Guildgate

This land enters tapped.
{T}: Add {U} or {B}.

Growth Spiral

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

Command Tower

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

Tireless Tracker

Landfall — Whenever a land you control enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Whenever you sacrifice a Clue, put a +1/+1 counter on Tireless Tracker.

Glaive of the Guildpact

Equipped creature gets +1/+0 for each Gate you control and has vigilance and menace. (A creature with menace can't be blocked except by two or more creatures.)
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

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.

Gatecreeper Vine

Defender
When Gatecreeper Vine enters, you may search your library for a basic land card or a Gate card, reveal it, put it into your hand, then shuffle.

Perennial Behemoth

You may play lands from your graveyard.
Unearth {G}{G} ({G}{G}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Scapeshift

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

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Nine-Fingers Keene

Menace
Ward—Pay 9 life.
Whenever Nine-Fingers Keene deals combat damage to a player, look at the top nine cards of your library. You may put a Gate card from among them onto the battlefield. Then if you control nine or more Gates, put the rest into your hand. Otherwise, put the rest on the bottom of your library in a random order.

Mirrorpool

Mirrorpool enters tapped.
{T}: Add {C}.
{2}{C}, {T}, Sacrifice Mirrorpool: Copy target instant or sorcery spell you control. You may choose new targets for the copy.
{4}{C}, {T}, Sacrifice Mirrorpool: Create a token that's a copy of target creature you control.

Aqueous Form

Enchant creature
Enchanted creature can't be blocked.
Whenever enchanted creature attacks, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Reshape the Earth

Search your library for up to ten land cards, put them onto the battlefield tapped, then shuffle.

Sylvan Scrying

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