Maybe 

Omnath, Locus of Rage

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

Definitely 

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.

Abundance

If you would draw a card, you may instead choose land or nonland and reveal cards from the top of your library until you reveal a card of the chosen kind. Put that card into your hand and put all other cards revealed this way on the bottom of your library in any order.

Fecund Greenshell

Reach
As long as you control ten or more lands, creatures you control get +2/+2.
Whenever this creature or another creature you control with toughness greater than its power enters, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped. Otherwise, put it into your hand.

Mossborn Hydra

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
This creature enters with a +1/+1 counter on it.
Landfall — Whenever a land you control enters, double the number of +1/+1 counters on this creature.

Reap the Past

Return X cards at random from your graveyard to your hand. Exile Reap the Past.

Reclamation Sage

When this creature enters, you may destroy target artifact or enchantment.

Kodama of the East Tree

Reach
Whenever another permanent you control enters, if it wasn't put onto the battlefield with this ability, you may put a permanent card with equal or lesser mana value from your hand onto the battlefield.
Partner (You can have two commanders if both have partner.)

Loot, Exuberant Explorer

You may play an additional land on each of your turns.
{4}{G}{G}, {T}: Look at the top six cards of your library. You may reveal a creature card with mana value less than or equal to the number of lands you control from among them and put it onto the battlefield. Put the rest on the bottom in a random order.

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.

Cloudshift

Exile target creature you control, then return that card to the battlefield under your control.

Cabaretti Courtyard

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

Izzet Boilerworks

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {U}{R}.

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."

Jwari Ruins

Jwari Disruption

Counter target spell unless its controller pays {1}.

Jwari Disruption // Jwari Ruins

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.

Ashaya, Soul of the Wild

Ashaya'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.)

Animist's Awakening

Reveal the top X cards of your library. Put all land cards from among them onto the battlefield tapped and the rest on the bottom of your library in a random order.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, untap those lands.

Obuun, Mul Daya Ancestor

At the beginning of combat on your turn, up to one target land you control becomes an X/X Elemental creature with trample and haste until end of turn, where X is Obuun's power. It's still a land.
Landfall — Whenever a land you control enters, put a +1/+1 counter on target creature.

Negate

Grasslands

This land enters tapped.
{T}, Sacrifice this land: Search your library for a Forest or Plains card, put it onto the battlefield, then shuffle.

Emeria Angel

Flying
Landfall — Whenever a land you control enters, you may create a 1/1 white Bird creature token with flying.

Lotus Cobra

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

Nissa, Vital Force

+1: Untap target land you control. Until your next turn, it becomes a 5/5 Elemental creature with haste. It's still a land.
−3: Return target permanent card from your graveyard to your hand.
−6: You get an emblem with "Whenever a land you control enters, you may draw a card."

Coiling Oracle

When this creature enters, reveal the top card of your library. If it's a land card, put it onto the battlefield. Otherwise, put that card into your hand.

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.

Frontier Bivouac

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

Selesnya Guildgate

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

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.

Canopy Vista

({T}: Add {G} or {W}.)
This land enters tapped unless you control two or more basic lands.

Spelunking

When this enchantment 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.

Bant Panorama

{T}: Add {C}.
{1}, {T}, Sacrifice this land: Search your library for a basic Forest, Plains, or Island card, put it onto the battlefield tapped, then shuffle.

Blackblade Reforged

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

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.

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.

Escape Tunnel

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
{T}, Sacrifice this land: Target creature with power 2 or less can't be blocked this turn.

Mountain Valley

This land enters tapped.
{T}, Sacrifice this land: Search your library for a Mountain or Forest card, put it onto the battlefield, then shuffle.

Planar Genesis

Look at the top four cards of your library. You may put a land card from among them onto the battlefield tapped. If you don't, put a card from among them into your hand. Put the rest on the bottom of your library in a random order.

Heroic Intervention

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

Fertilid

This creature enters with two +1/+1 counters on it.
{1}{G}, Remove a +1/+1 counter from this creature: Target player searches their library for a basic land card, puts it onto the battlefield tapped, then shuffles.

Exploration

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

Tatyova, Benthic Druid

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

Fertile Footsteps

Search your library for a basic land card, put it onto the battlefield, then shuffle. (Then exile this card. You may cast the creature later from exile.)

Beanstalk Giant

Beanstalk Giant's power and toughness are each equal to the number of lands you control.

Beanstalk Giant // Fertile Footsteps

Eureka Moment

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

Ruin Ghost

{W}, {T}: Exile target land you control, then return it to the battlefield under your control.

Survive

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Each player shuffles their graveyard into their library.

Struggle

Struggle deals damage to target creature equal to the number of lands you control.

Struggle // Survive

Growth Spiral

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

Felidar Retreat

Landfall — Whenever a land you control enters, choose one —
• Create a 2/2 white Cat Beast creature token.
• Put a +1/+1 counter on each creature you control. Those creatures gain vigilance until end of turn.

Plains

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.

Meloku the Clouded Mirror

Flying
{1}, Return a land you control to its owner's hand: Create a 1/1 blue Illusion creature token with flying.

Tranquil Landscape

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

Teferi's Protection

Until your next turn, your life total can't change and you gain protection from everything. All permanents you control phase out. (While they're phased out, they're treated as though they don't exist. They phase in before you untap during your untap step.)
Exile Teferi's Protection.

Seaside Citadel

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

Sheltering Landscape

{T}: Add {C}.
{T}, Sacrifice this land: Search your library for a basic Mountain, Forest, or Plains card, put it onto the battlefield tapped, then shuffle.
Cycling {R}{G}{W} ({R}{G}{W}, Discard this card: Draw a card.)

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.

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.

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.

Emeria Shepherd

Flying
Landfall — Whenever a land you control enters, you may return target nonland permanent card from your graveyard to your hand. If that land is a Plains, you may return that nonland permanent card to the battlefield instead.

Ramunap Excavator

Sol Ring

Command Tower

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

Zimone, Mystery Unraveler

Landfall — Whenever a land you control enters, manifest dread if this is the first time this ability has resolved this turn. Otherwise, you may turn a permanent you control face up. (To manifest dread, look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Rites of Flourishing

At the beginning of each player's draw step, that player draws an additional card.
Each player may play an additional land on each of their turns.

Counterspell

Ghostly Flicker

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Kodama's Reach

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.)

Nature's Claim

Destroy target artifact or enchantment. Its controller gains 4 life.

Boros Garrison

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {R}{W}.

Seer's Sundial

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

Naya Charm

Choose one —
• Naya Charm deals 3 damage to target creature.
• Return target card from a graveyard to its owner's hand.
• Tap all creatures target player controls.

Farseek

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

Perilous Landscape

{T}: Add {C}.
{T}, Sacrifice this land: Search your library for a basic Island, Mountain, or Plains card, put it onto the battlefield tapped, then shuffle.
Cycling {U}{R}{W} ({U}{R}{W}, Discard this card: Draw a card.)

Riveteers Overlook

When this land enters, 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.

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.

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.

Living Twister

{1}{R}, Discard a land card: This creature deals 2 damage to any target.
{G}: Return a tapped land you control to its owner's hand.

Geode Rager

First strike
Landfall — Whenever a land you control enters, goad each creature target player controls. (Until your next turn, those creatures attack each combat if able and attack a player other than you if able.)

Multani, Yavimaya's Avatar

Reach, trample
Multani gets +1/+1 for each land you control and each land card in your graveyard.
{1}{G}, Return two lands you control to their owner's hand: Return this card from your graveyard to your hand.

Risen Reef

Whenever this creature or another Elemental you control enters, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped. If you don't put the card onto the battlefield, put it into your hand.

Explore

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

Cultivator Colossus

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

Murasa Rootgrazer

Vigilance
{T}: You may put a basic land card from your hand onto the battlefield.
{T}: Return target basic land you control to its owner's hand.

Wayfarer's Bauble

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

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.

Simic Growth Chamber

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {G}{U}.

Myriad Landscape

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

Prairie Stream

({T}: Add {W} or {U}.)
This land enters tapped unless you control two or more basic lands.

Forest

Spitfire Lagac

Landfall — Whenever a land you control enters, this creature deals 1 damage to each opponent.

Naya Panorama

{T}: Add {C}.
{1}, {T}, Sacrifice this land: Search your library for a basic Mountain, Forest, or Plains card, put it onto the battlefield tapped, then shuffle.

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 token: You gain 3 life." Treasure is an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

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.")

Yasharn, Implacable Earth

When Yasharn enters, search your library for a basic Forest card and a basic Plains card, reveal those cards, put them into your hand, then shuffle.
Players can't pay life or sacrifice nonland permanents to cast spells or activate abilities.

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.

Dragonback Assault

When this enchantment enters, it deals 3 damage to each creature and each planeswalker.
Landfall — Whenever a land you control enters, create a 4/4 red Dragon creature token with flying.

Omnath, Locus of the Roil

When Omnath enters, it deals damage to any target equal to the number of Elementals you control.
Landfall — Whenever a land you control enters, put a +1/+1 counter on target Elemental you control. If you control eight or more lands, draw a card.