Ghalta, Primal Hunger

This spell costs {X} less to cast, where X is the total power of creatures you control.
Trample

Ancient Crab

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.

Terastodon

When Terastodon enters the battlefield, you may destroy up to three target noncreature permanents. For each permanent put into a graveyard this way, its controller creates a 3/3 green Elephant creature token.

Dawnhart Rejuvenator

When Dawnhart Rejuvenator enters the battlefield, you gain 3 life.
{T}: Add one mana of any color.

Shipbreaker Kraken

{6}{U}{U}: Monstrosity 4. (If this creature isn't monstrous, put four +1/+1 counters on it and it becomes monstrous.)
When Shipbreaker Kraken becomes monstrous, tap up to four target creatures. Those creatures don't untap during their controllers' untap steps for as long as you control Shipbreaker Kraken.

Yavimaya Elder

When Yavimaya Elder dies, you may search your library for up to two basic land cards, reveal them, put them into your hand, then shuffle.
{2}, Sacrifice Yavimaya Elder: Draw a card.

Fact or Fiction

Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Command Tower

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

Prosperous Pirates

When Prosperous Pirates enters the battlefield, create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Peel from Reality

Return target creature you control and target creature you don't control to their owners' hands.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Rise of the Ants

Create two 3/3 green Insect creature tokens. You gain 2 life.
Flashback {6}{G}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Eternal Witness

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

Primal Bellow

Target creature gets +1/+1 until end of turn for each Forest you control.

Ramunap Excavator

Coral Atoll

Coral Atoll enters the battlefield tapped.
When Coral Atoll enters the battlefield, sacrifice it unless you return an untapped Island you control to its owner's hand.
{T}: Add {C}{U}.

Reliquary Tower

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

Marwyn, the Nurturer

Whenever another Elf enters the battlefield under your control, put a +1/+1 counter on Marwyn, the Nurturer.
{T}: Add an amount of {G} equal to Marwyn's power.

Sol Ring

Arbor Colossus

Reach
{3}{G}{G}{G}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
When Arbor Colossus becomes monstrous, destroy target creature with flying an opponent controls.

Memorial to Genius

Memorial to Genius enters the battlefield tapped.
{T}: Add {U}.
{4}{U}, {T}, Sacrifice Memorial to Genius: Draw two cards.

Stumpsquall Hydra

When Stumpsquall Hydra enters the battlefield, distribute X +1/+1 counters among it and any number of commanders.

Explore

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

Search for Tomorrow

Search your library for a basic land card, put it onto the battlefield, then shuffle.
Suspend 2—{G} (Rather than cast this card from your hand, you may pay {G} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Simic Growth Chamber

Simic Growth Chamber enters the battlefield tapped.
When Simic Growth Chamber enters the battlefield, return a land you control to its owner's hand.
{T}: Add {G}{U}.

Silburlind Snapper

Silburlind Snapper can't attack unless you've cast a noncreature spell this turn.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Awakener Druid

When Awakener Druid enters the battlefield, target Forest becomes a 4/5 green Treefolk creature for as long as Awakener Druid remains on the battlefield. It's still a land.

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.

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.

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Reclamation Sage

When Reclamation Sage enters the battlefield, you may destroy target artifact or enchantment.

Whelming Wave

Return all creatures to their owners' hands except for Krakens, Leviathans, Octopuses, and Serpents.

Drownyard Explorers

When Drownyard Explorers enters the battlefield, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Evolving Wilds

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

Omenspeaker

When Omenspeaker enters the battlefield, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

Compulsive Research

Target player draws three cards. Then that player discards two cards unless they discard a land card.

Wave-Wing Elemental

Flying
Landfall — Whenever a land enters the battlefield under your control, Wave-Wing Elemental gets +2/+2 until end of turn.

Beast Within

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

Sporemound

Landfall — Whenever a land enters the battlefield under your control, create a 1/1 green Saproling creature token.

Trench Behemoth

Return a land you control to its owner's hand: Untap Trench Behemoth. It gains hexproof until end of turn.
Landfall — Whenever a land enters the battlefield under your control, target creature an opponent controls attacks during its controller's next combat phase if able.

Urban Evolution

Draw three cards. You may play an additional land this turn.

Verdant Sun's Avatar

Whenever Verdant Sun's Avatar or another creature enters the battlefield under your control, you gain life equal to that creature's toughness.

Forest

Scourge of Fleets

When Scourge of Fleets enters the battlefield, return each creature your opponents control with toughness X or less to its owner's hand, where X is the number of Islands you control.

Stormtide Leviathan

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
All lands are Islands in addition to their other types.
Creatures without flying or islandwalk can't attack.

Vivid Grove

Vivid Grove enters the battlefield tapped with two charge counters on it.
{T}: Add {G}.
{T}, Remove a charge counter from Vivid Grove: Add one mana of any color.

Ior Ruin Expedition

Landfall — Whenever a land enters the battlefield under your control, you may put a quest counter on Ior Ruin Expedition.
Remove three quest counters from Ior Ruin Expedition and sacrifice it: Draw two cards.

Aesi, Tyrant of Gyre Strait

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

Nezahal, Primal Tide

This spell can't be countered.
You have no maximum hand size.
Whenever an opponent casts a noncreature spell, draw a card.
Discard three cards: Exile Nezahal, Primal Tide. Return it to the battlefield tapped under its owner's control at the beginning of the next end step.

Molimo, Maro-Sorcerer

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Molimo, Maro-Sorcerer's power and toughness are each equal to the number of lands you control.

Sharktocrab

{2}{G}{U}: Adapt 1. (If this creature has no +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever one or more +1/+1 counters are put on Sharktocrab, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Acidic Slime

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When Acidic Slime enters the battlefield, destroy target artifact, enchantment, or land.

Brinelin, the Moon Kraken

When Brinelin, the Moon Kraken enters the battlefield or whenever you cast a spell with mana value 6 or greater, you may return target nonland permanent to its owner's hand.
Partner (You can have two commanders if both have partner.)

Wickerbough Elder

Wickerbough Elder enters the battlefield with a -1/-1 counter on it.
{G}, Remove a -1/-1 counter from Wickerbough Elder: Destroy target artifact or enchantment.

Bull's Strength

Target creature gets +2/+2 and gains trample until end of turn. Untap it.

Slinn Voda, the Rising Deep

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)
When Slinn Voda, the Rising Deep enters the battlefield, if it was kicked, return all creatures to their owners' hands except for Merfolk, Krakens, Leviathans, Octopuses, and Serpents.

Counterspell

Vivid Creek

Vivid Creek enters the battlefield tapped with two charge counters on it.
{T}: Add {U}.
{T}, Remove a charge counter from Vivid Creek: Add one mana of any color.

Thornwood Falls

Thornwood Falls enters the battlefield tapped.
When Thornwood Falls enters the battlefield, you gain 1 life.
{T}: Add {G} or {U}.

Retreat to Kazandu

Landfall — Whenever a land enters the battlefield under your control, choose one —
• Put a +1/+1 counter on target creature.
• You gain 2 life.

Rampaging Baloths

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

Blighted Woodland

{T}: Add {C}.
{3}{G}, {T}, Sacrifice Blighted Woodland: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Harmonize

Murkfiend Liege

Other green creatures you control get +1/+1.
Other blue creatures you control get +1/+1.
Untap all green and/or blue creatures you control during each other player's untap step.

Cultivate

Seer's Sundial

Landfall — Whenever a land enters the battlefield under your control, you may pay {2}. If you do, draw a card.

Elvish Aberration

{T}: Add {G}{G}{G}.
Forestcycling {2} ({2}, Discard this card: Search your library for a Forest card, reveal it, put it into your hand, then shuffle.)