Have

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.

Azusa, Lost but Seeking

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

Gruul Turf

Gruul Turf enters the battlefield tapped.
When Gruul Turf enters the battlefield, return a land you control to its owner's hand.
{T}: Add {R}{G}.

Echoing Deeps

You may have Echoing Deeps enter the battlefield tapped as a copy of any land card in a graveyard, except it's a Cave in addition to its other types.
{T}: Add {C}.

Don't Have

Worldly Tutor

Search your library for a creature card, reveal it, then shuffle and put the card on top.

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 enters the battlefield under your control, create a 3/3 green Badger creature token.

Three Visits

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

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Aftermath Analyst

When Aftermath Analyst enters the battlefield, mill three cards.
{3}{G}, Sacrifice Aftermath Analyst: Return all land cards from your graveyard to the battlefield tapped.

Arena

{3}, {T}: Tap target creature you control and target creature of an opponent's choice they control. Those creatures fight each other. (Each deals damage equal to its power to the other.)

Cactus Preserve

Cactus Preserve enters the battlefield tapped.
{T}: Add one mana of any type that a land you control could produce.
{3}: Until end of turn, Cactus Preserve becomes an X/X green Plant creature with reach, where X is the greatest mana value among your commanders. It's still a land.

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

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.

Ominous Cemetery

{T}: Add {C}.
{5}, {T}, Exile Ominous Cemetery: Target creature's owner shuffles it into their library.

Labyrinth of Skophos

{T}: Add {C}.
{4}, {T}: Remove target attacking or blocking creature from combat.

Maybe 

Nephalia Academy

If a spell or ability an opponent controls causes you to discard a card, you may reveal that card and put it on top of your library instead of putting it anywhere else.
{T}: Add {C}.

Riveteers Overlook

When Riveteers Overlook enters the battlefield, sacrifice it. When you do, search your library for a basic Swamp, Mountain, or Forest card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Defense of the Heart

At the beginning of your upkeep, if an opponent controls three or more creatures, sacrifice Defense of the Heart, search your library for up to two creature cards, put those cards onto the battlefield, then shuffle.

Tunneling Geopede

Landfall — Whenever a land enters the battlefield under your control, Tunneling Geopede deals 1 damage to each opponent.

Wilderness Reclamation

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

Exploration

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

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.

Mortuary Mire

Mortuary Mire enters the battlefield tapped.
When Mortuary Mire enters the battlefield, you may put target creature card from your graveyard on top of your library.
{T}: Add {B}.

Scapeshift

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

Omnath, Locus of Rage

Landfall — Whenever a land enters the battlefield under your control, create a 5/5 red and green Elemental creature token.
Whenever Omnath, Locus of Rage or another Elemental you control dies, Omnath deals 3 damage to any target.

Natural Order

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

Underground Mortuary

({T}: Add {B} or {G}.)
Underground Mortuary enters the battlefield tapped.
When Underground Mortuary enters the battlefield, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Urza's Cave

{T}: Add {C}.
{3}, {T}, Sacrifice Urza's Cave: Search your library for a land card, put it onto the battlefield tapped, then shuffle.

Mirrorpool

Mirrorpool enters the battlefield 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.

Crucible of Worlds

Myriad Landscape

Myriad Landscape enters the battlefield 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.

Ulvenwald Hydra

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

Nylea's Intervention

Choose one —
• Search your library for up to X land cards, reveal them, put them into your hand, then shuffle.
• Nylea's Intervention deals twice X damage to each creature with flying.

Horn of Greed

Whenever a player plays a land, that player draws a card.

Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Blighted Fen

{T}: Add {C}.
{4}{B}, {T}, Sacrifice Blighted Fen: Target opponent sacrifices a creature.

Inkmoth Nexus

{T}: Add {C}.
{1}: Inkmoth Nexus becomes a 1/1 Phyrexian Blinkmoth artifact creature with flying and infect until end of turn. It's still a land. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

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.

Field of the Dead

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

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.

Zendikar's Roil

Landfall — Whenever a land enters the battlefield under your control, create a 2/2 green Elemental creature token.

Ormendahl, Profane Prince

Westvale Abbey

{T}: Add {C}.
{5}, {T}, Pay 1 life: Create a 1/1 white and black Human Cleric creature token.
{5}, {T}, Sacrifice five creatures: Transform Westvale Abbey, then untap it.

Westvale Abbey // Ormendahl, Profane Prince

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.

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.

Blinkmoth Nexus

{T}: Add {C}.
{1}: Blinkmoth Nexus becomes a 1/1 Blinkmoth artifact creature with flying until end of turn. It's still a land.
{1}, {T}: Target Blinkmoth creature gets +1/+1 until end of turn.

Craterhoof Behemoth

Haste
When Craterhoof Behemoth enters the battlefield, creatures you control gain trample and get +X/+X until end of turn, where X is the number of creatures you control.

Yavimaya, Cradle of Growth

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

Lord Windgrace

+2: Discard a card, then draw a card. If a land card is discarded this way, draw an additional card.
−3: Return up to two target land cards from your graveyard to the battlefield.
−11: Destroy up to six target nonland permanents, then create six 2/2 green Cat Warrior creature tokens with forestwalk.
Lord Windgrace can be your commander.

Thespian's Stage

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

Eternal Witness

When Eternal Witness enters the battlefield, you may return target card from your graveyard to your hand.

Ramunap Excavator

Seedborn Muse

Untap all permanents you control during each other player's untap step.

Retreat to Hagra

Landfall — Whenever a land enters the battlefield under your control, choose one —
• Target creature gets +1/+0 and gains deathtouch until end of turn.
• Each opponent loses 1 life and you gain 1 life.

Command Tower

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

Swamp

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.

Emergence Zone

{T}: Add {C}.
{1}, {T}, Sacrifice Emergence Zone: You may cast spells this turn as though they had flash.

Maze of Ith

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

Spelunking

When Spelunking enters the battlefield, 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 the battlefield untapped.

Lotus Cobra

Landfall — Whenever a land enters the battlefield under your control, add one mana of any color.

Ziatora's Proving Ground

({T}: Add {B}, {R}, or {G}.)
Ziatora's Proving Ground enters the battlefield tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

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 the battlefield, sacrifice a land.
Creatures you control can't attack.
Prevent all damage that would be dealt to you.

Deflecting Swat

If you control a commander, you may cast this spell without paying its mana cost.
You may choose new targets for target spell or ability.

Cultivator Colossus

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

Underdark Rift

{T}: Add {C}.
{5}, {T}, Exile Underdark Rift: Roll a d10. Put target artifact, creature, or planeswalker into its owner's library just beneath the top X cards of that library, where X is the result. Activate only as a sorcery.

Diamond City

Diamond City enters the battlefield with a shield counter on it. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)
{T}: Add {C}.
{T}: Move a shield counter from Diamond City onto target creature. Activate only if two or more creatures entered the battlefield under your control this turn.

Ob Nixilis, the Fallen

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

Realm Seekers

Realm Seekers enters the battlefield with X +1/+1 counters on it, where X is the total number of cards in all players' hands.
{2}{G}, Remove a +1/+1 counter from Realm Seekers: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Lair of the Hydra

If you control two or more other lands, Lair of the Hydra enters the battlefield tapped.
{T}: Add {G}.
{X}{G}: Until end of turn, Lair of the Hydra becomes an X/X green Hydra creature. It's still a land. X can't be 0.

Mina and Denn, Wildborn

You may play an additional land on each of your turns.
{R}{G}, Return a land you control to its owner's hand: Target creature gains trample until end of turn.

Gargoyle Castle

{T}: Add {C}.
{5}, {T}, Sacrifice Gargoyle Castle: Create a 3/4 colorless Gargoyle artifact creature token with flying.

Rampaging Baloths

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

Splendid Reclamation

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

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Vesuva

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

Archdruid's Charm

Choose one —
• Search your library for a creature or land card and reveal it. Put it onto the battlefield tapped if it's a land card. Otherwise, put it into your hand. Then shuffle.
• Put a +1/+1 counter on target creature you control. It deals damage equal to its power to target creature you don't control.
• Exile target artifact or enchantment.

Blossoming Tortoise

Whenever Blossoming Tortoise enters the battlefield or attacks, mill three cards, then return a land card from your graveyard to the battlefield tapped.
Activated abilities of lands you control cost {1} less to activate.
Land creatures you control get +1/+1.

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.

Ancient Greenwarden

Reach
You may play lands from your graveyard.
If a land entering the battlefield causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Cavalier of Thorns

Reach
When Cavalier of Thorns enters the battlefield, reveal the top five cards of your library. Put a land card from among them onto the battlefield and the rest into your graveyard.
When Cavalier of Thorns dies, you may exile it. If you do, put another target card from your graveyard on top of your library.

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.

Scute Swarm

Landfall — Whenever a land enters the battlefield under your control, 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.

Worldsoul's Rage

Worldsoul's Rage deals X damage to any target. Put up to X land cards from your hand and/or graveyard onto the battlefield tapped.

Reliquary Tower

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

Tiller Engine

Whenever a land enters the battlefield tapped and under your control, choose one —
• Untap that land.
• Tap target nonland permanent an opponent controls.

Dark Depths

Dark Depths enters the battlefield with ten ice counters on it.
{3}: Remove an ice counter from Dark Depths.
When Dark Depths has no ice counters on it, sacrifice it. If you do, create Marit Lage, a legendary 20/20 black Avatar creature token with flying and indestructible.

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.

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}.

Avenger of Zendikar

When Avenger of Zendikar enters the battlefield, create a 0/1 green Plant creature token for each land you control.
Landfall — Whenever a land enters the battlefield under your control, you may put a +1/+1 counter on each Plant creature you control.

Memorial to Folly

Memorial to Folly enters the battlefield tapped.
{T}: Add {B}.
{2}{B}, {T}, Sacrifice Memorial to Folly: Return target creature card from your graveyard to your hand.

Mountain

Lotus Field

Hexproof
Lotus Field enters the battlefield tapped.
When Lotus Field enters the battlefield, sacrifice two lands.
{T}: Add three mana of any one color.

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.

Forest

Deadly Rollick

If you control a commander, you may cast this spell without paying its mana cost.
Exile target creature.