Aetherize

Return all attacking creatures to their owner's hand.

Fierce Guardianship

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

Hedron Crab

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

Castle Vantress

Castle Vantress enters tapped unless you control an Island.
{T}: Add {U}.
{2}{U}{U}, {T}: Scry 2.

Crystacean

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

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.

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.

Twisted Image

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

Kindred Discovery

As this enchantment enters, choose a creature type.
Whenever a creature you control of the chosen type enters or attacks, draw a card.

Rite of Replication

Kicker {5} (You may pay an additional {5} as you cast this spell.)
Create a token that's a copy of target creature. If this spell was kicked, create five of those tokens instead.

Disallow

Counter target spell, activated ability, or triggered ability. (Mana abilities can't be targeted.)

Curse of the Swine

Exile X target creatures. For each creature exiled this way, its controller creates a 2/2 green Boar creature token.

Blackblade Reforged

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

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Sapphire Medallion

Blue spells you cast cost {1} less to cast.

Snow-Covered Island

Mutavault

{T}: Add {C}.
{1}: This land becomes a 2/2 creature with all creature types until end of turn. It's still a land.

Reality Shift

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

Jwari Scuttler

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.

Coat of Arms

Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Goblin Warriors and a Goblin Shaman are on the battlefield, each gets +2/+2.)

Arcane Signet

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

Narset's Reversal

Copy target instant or sorcery spell, then return it to its owner's hand. You may choose new targets for the copy.

Wishcoin Crab

Counterspell

Devastation Tide

Return all nonland permanents to their owners' hands.
Miracle {1}{U} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

Shadowspear

Equipped creature gets +1/+1 and has trample and lifelink.
{1}: Permanents your opponents control lose hexproof and indestructible until end of turn.
Equip {2}

Strata Scythe

Imprint — When this Equipment enters, search your library for a land card, exile it, then shuffle.
Equipped creature gets +1/+1 for each land on the battlefield with the same name as the exiled card.
Equip {3}

Horseshoe Crab

Adaptive Automaton

As this creature enters, choose a creature type.
This creature is the chosen type in addition to its other types.
Other creatures you control of the chosen type get +1/+1.

Hightide Hermit

Defender
When this creature enters, you get {E}{E}{E}{E} (four energy counters).
Pay {E}{E}: This creature can attack this turn as though it didn't have defender.

Ancient Crab

Windfall

Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Fortress Crab

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.)

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Crab Umbra

Enchant creature
{2}{U}: Untap enchanted creature.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

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.

Darksteel Plate

Indestructible
Equipped creature has indestructible.
Equip {2}

Strip Mine

{T}: Add {C}.
{T}, Sacrifice this land: Destroy target land.

Engulf the Shore

Return to their owners' hands all creatures with toughness less than or equal to the number of Islands you control.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Salvage Scuttler

Whenever this creature attacks, return an artifact you control to its owner's hand.

Rhystic Study

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

Cryptic Command

Choose two —
• Counter target spell.
• Return target permanent to its owner's hand.
• Tap all creatures your opponents control.
• Draw a card.

Negate

Sword of the Animist

Equipped creature gets +1/+1.
Whenever equipped creature attacks, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Equip {2}

Pongify

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

Iceberg Cancrix

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

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.

Mystic Sanctuary

({T}: Add {U}.)
This land enters tapped unless you control three or more other Islands.
When this land enters untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Wormfang Crab

This creature can't be blocked.
When this creature enters, an opponent chooses a permanent you control other than this creature and exiles it.
When this creature leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Commander's Plate

Equipped creature gets +3/+3 and has protection from each color that's not in your commander's color identity.
Equip commander {3}
Equip {5}

Purple-Crystal Crab

Skittering Crustacean

{6}{U}: Monstrosity 4. (If this creature isn't monstrous, put four +1/+1 counters on it and it becomes monstrous.)
As long as this creature is monstrous, it has hexproof. (It can't be the target of spells or abilities your opponents control.)

Buried Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice this land: Return target artifact card from your graveyard to your hand.

Homeward Path

{T}: Add {C}.
{T}: Each player gains control of all creatures they own.

Armored Cancrix

Minamo, School at Water's Edge

{T}: Add {U}.
{U}, {T}: Untap target legendary permanent.

Skitter Eel

{2}{U}: Adapt 2. (If this creature has no +1/+1 counters on it, put two +1/+1 counters on it.)

Eel Umbra

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature gets +1/+1.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Oraxid

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.

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.

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.")

Flow of Ideas

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.)

Giant Crab

{U}: This creature gains shroud until end of turn. (It can't be the target of spells or abilities.)

Ponder

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

Bident of Thassa

Whenever a creature you control deals combat damage to a player, you may draw a card.
{1}{U}, {T}: Creatures your opponents control attack this turn if able.

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.