Three Visits

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

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 this creature, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Scuttletide

{1}, Discard a card: Create a 0/3 blue Crab creature token.
Delirium — Crabs you control get +1/+1 as long as there are four or more card types among cards in your graveyard.

Rally the Ranks

As this enchantment enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.

Kefnet's Monument

Blue creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, target creature an opponent controls doesn't untap during its controller's next untap step.

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Azorius Chancery

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

Simic Keyrune

{T}: Add {G} or {U}.
{G}{U}: This artifact becomes a 2/3 green and blue Crab artifact creature with hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Drownyard Behemoth

Flash (You may cast this spell any time you could cast an instant.)
Emerge {7}{U} (You may cast this spell by sacrificing a creature and paying the emerge cost reduced by that creature's mana value.)
This creature has hexproof as long as it entered this turn.

Huatli, the Sun's Heart

Each creature you control assigns combat damage equal to its toughness rather than its power.
−3: You gain life equal to the greatest toughness among creatures you control.

Fortress Crab

Nature's Claim

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

Hinterland Harbor

This land enters tapped unless you control a Forest or an Island.
{T}: Add {G} or {U}.

Realmwalker

Changeling (This card is every creature type.)
As this creature enters, choose a creature type.
You may look at the top card of your library any time.
You may cast creature spells of the chosen type from the top of your library.

Sol Ring

Ruin Crab

Landfall — Whenever a land you control enters, each opponent mills three cards. (To mill a card, a player puts the top card of their library into their graveyard.)

Dreadlight Monstrosity

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
{3}{U}{U}: This creature can't be blocked this turn. Activate only if you own a card in exile.

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Stroke of Midnight

Destroy target nonland permanent. Its controller creates a 1/1 white Human creature token.

Prairie Stream

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

Hard Evidence

Create a 0/3 blue Crab creature token.
Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Wave of Reckoning

Each creature deals damage to itself equal to its power.

Herald's Horn

As this artifact enters, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Twisted Image

Switch target creature's power and toughness until end of turn.
Draw a card.

Nature's Lore

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

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Shambleshark

Flash (You may cast this spell any time you could cast an instant.)
Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Overgrown Farmland

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

Fell the Mighty

Destroy all creatures with power greater than target creature's power.

Reliquary Tower

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

Guardian Project

Whenever a nontoken creature you control enters, if it doesn't have the same name as another creature you control or a creature card in your graveyard, draw a card.

Adarkar Wastes

{T}: Add {C}.
{T}: Add {W} or {U}. This land deals 1 damage to you.

Glacial Fortress

This land enters tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Chulane, Teller of Tales

Vigilance
Whenever you cast a creature spell, draw a card, then you may put a land card from your hand onto the battlefield.
{3}, {T}: Return target creature you control to its owner's hand.

High Alert

Each creature you control assigns combat damage equal to its toughness rather than its power.
Creatures you control can attack as though they didn't have defender.
{2}{W}{U}: Untap target creature.

Beast Whisperer

Whenever you cast a creature spell, draw a card.

Farseek

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

Ancient Crab

Hedron Crab

Landfall — Whenever a land you control enters, target player mills three cards.

Sakura-Tribe Elder

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

Charix, the Raging Isle

Spells your opponents cast that target Charix cost {2} more to cast.
{3}: Charix gets +X/-X until end of turn, where X is the number of Islands you control.

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}.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Levitation

Door of Destinies

As this artifact enters, choose a creature type.
Whenever you cast a spell of the chosen type, put a charge counter on this artifact.
Creatures you control of the chosen type get +1/+1 for each charge counter on this artifact.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Snow-Covered Plains

Command Tower

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

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.

Mirrorshell Crab

Ward {3} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)
Channel — {2}{U}, Discard this card: Counter target spell or ability unless its controller pays {3}.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Icon of Ancestry

As this artifact enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{3}, {T}: Look at the top three cards of your library. You may reveal a creature card of the chosen type from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Seaside Citadel

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

Brushland

{T}: Add {C}.
{T}: Add {G} or {W}. This land deals 1 damage to you.

Reflections of Littjara

As this enchantment enters, choose a creature type.
Whenever you cast a spell of the chosen type, copy that spell. (A copy of a permanent spell becomes a token.)

Dreamroot Cascade

This land enters tapped unless you control two or more other lands.
{T}: Add {G} or {U}.

Tower Defense

Creatures you control get +0/+5 and gain reach until end of turn.

Purple-Crystal Crab

Horseshoe Crab

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Snow-Covered Forest

Thassa's Emissary

Bestow {5}{U} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Whenever this creature or enchanted creature deals combat damage to a player, draw a card.
Enchanted creature gets +3/+3.

Sunpetal Grove

This land enters tapped unless you control a Forest or a Plains.
{T}: Add {G} or {W}.

Snow-Covered Island

Selesnya Sanctuary

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

Cultivate

Assault Formation

Each creature you control assigns combat damage equal to its toughness rather than its power.
{G}: Target creature with defender can attack this turn as though it didn't have defender.
{2}{G}: Creatures you control get +0/+1 until end of turn.

Unnatural Growth

At the beginning of each combat, double the power and toughness of each creature you control until end of turn.

Instruments of War

Flash
As this artifact enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.

Distant Melody

Choose a creature type. Draw a card for each permanent you control of that type.

Rasaad yn Bashir

Each creature you control assigns combat damage equal to its toughness rather than its power.
Whenever Rasaad yn Bashir attacks, if you have the initiative, double the toughness of each creature you control until end of turn.
Choose a Background (You can have a Background as a second commander.)

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Pongify

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

Crystacean

Flash (You may cast this spell any time you could cast an instant.)

Stoneskin

Flash
Enchant creature
Enchanted creature gets +0/+10.

Rampant Growth

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

Iceberg Cancrix

Whenever another snow permanent you control enters, you may have target player mill two cards.

King Crab

{1}{U}, {T}: Put target green creature on top of its owner's library.

Vanquisher's Banner

As this artifact enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

Skyshroud Claim

Search your library for up to two Forest cards, put them onto the battlefield, then shuffle.

Shore Up

Target creature you control gets +1/+1 and gains hexproof until end of turn. Untap it. (It can't be the target of spells or abilities your opponents control.)

Riptide Crab

Vigilance
When this creature dies, draw a card.

Metallic Mimic

As this creature enters, choose a creature type.
This creature is the chosen type in addition to its other types.
Each other creature you control of the chosen type enters with an additional +1/+1 counter on it.

Chromeshell Crab

Morph {4}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When this creature is turned face up, you may exchange control of target creature you control and target creature an opponent controls.

Scuttlegator

Defender
{6}{G/U}{G/U}: Adapt 3. (If this creature has no +1/+1 counters on it, put three +1/+1 counters on it.)
As long as this creature has a +1/+1 counter on it, it can attack as though it didn't have defender.

Chromatic Lantern

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

Vexing Scuttler

Emerge {6}{U} (You may cast this spell by sacrificing a creature and paying the emerge cost reduced by that creature's mana value.)
When you cast this spell, you may return target instant or sorcery card from your graveyard to your hand.