Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.
{U}
Aqueous Form
Enchantment - Aura
Enchant creature
Enchanted creature can't be blocked.
Whenever enchanted creature attacks, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)
{2}
Arcane Signet
Artifact
{T}: Add one mana of any color in your commander's color identity.
{4}{U}
Armored Cancrix
Creature - Crab
2 /
5
{2}
Blackblade Reforged
Legendary Artifact - Equipment
Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}
--
Castle Vantress
Land
Castle Vantress enters the battlefield tapped unless you control an Island.
{T}: Add {U}.
{2}{U}{U}, {T}: Scry 2.
{2}{U}{U}
Charix, the Raging Isle
Legendary Creature - Leviathan Crab
Spells your opponents cast that target Charix, the Raging Isle cost {2} more to cast.
{3}: Charix gets +X/-X until end of turn, where X is the number of Islands you control.
0 /
17
{4}{U}
Chromeshell Crab
Creature - Crab Beast
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 Chromeshell Crab is turned face up, you may exchange control of target creature you control and target creature an opponent controls.
3 /
3
{2}{U}{U}
Clever Impersonator
Creature - Shapeshifter
You may have Clever Impersonator enter the battlefield as a copy of any nonland permanent on the battlefield.
0 /
0
{1}
Commander's Plate
Artifact - Equipment
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}
--
Coral Atoll
Land
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}.
{1}{U}{U}{U}
Cryptic Command
Instant
Choose two --
• Counter target spell.
• Return target permanent to its owner's hand.
• Tap all creatures your opponents control.
• Draw a card.
{3}{U}
Crystacean
Creature - Crab
Flash
1 /
6
{3}
Darksteel Plate
Artifact - Equipment
Indestructible
Equipped creature has indestructible.
Equip {2}
{9}
Drownyard Behemoth
Creature - Eldrazi Crab
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.)
Drownyard Behemoth has hexproof as long as it entered the battlefield this turn.
5 /
7
{3}{U}
Engulf the Shore
Instant
Return to their owners' hands all creatures with toughness less than or equal to the number of Islands you control.
--
Evolving Wilds
Land
{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
{U}{U}{U}
Fated Infatuation
Instant
Create a token that's a copy of target creature you control. If it's your turn, 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.)
{2}{U}
Fierce Guardianship
Instant
If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.
--
Flooded Strand
Land
{T}, Pay 1 life, Sacrifice Flooded Strand: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.
{1}{U}{U}
Force of Negation
Instant
If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost.
Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.
{3}{U}
Fortress Crab
Creature - Crab
1 /
6
{1}{U}
Frogify
Enchantment - Aura
Enchant creature
Enchanted creature loses all abilities and is a blue Frog creature with base power and toughness 1/1. (It loses all other card types and creature types.)
--
Halimar Depths
Land
Halimar Depths enters the battlefield tapped.
When Halimar Depths enters the battlefield, look at the top three cards of your library, then put them back in any order.
{T}: Add {U}.
{4}
Hammer of Nazahn
Legendary Artifact - Equipment
Whenever Hammer of Nazahn or another Equipment enters the battlefield under your control, you may attach that Equipment to target creature you control.
Equipped creature gets +2/+0 and has indestructible.
Equip {4}
{3}
Haunted Cloak
Artifact - Equipment
Equipped creature has vigilance, trample, and haste.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)
{U}
Hedron Crab
Creature - Crab
Landfall -- Whenever a land enters the battlefield under your control, target player mills three cards.
0 /
2
{U}
High Tide
Instant
Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.
{4}{U}
Hightide Hermit
Creature - Crab
Defender
When Hightide Hermit enters the battlefield, you get {E}{E}{E}{E} (four energy counters).
Pay {E}{E}: Hightide Hermit can attack this turn as though it didn't have defender.
4 /
4
{2}{U}
Horseshoe Crab
Creature - Crab
{U}: Untap Horseshoe Crab.
1 /
3
{1}{U}
Iceberg Cancrix
Snow Creature - Crab
Whenever another snow permanent enters the battlefield under your control, you may have target player mill two cards.
0 /
4
{2}{U}
Ichthyomorphosis
Enchantment - Aura
Enchant creature
Enchanted creature loses all abilities and is a blue Fish with base power and toughness 0/1.
{2}{U}
Imprisoned in the Moon
Enchantment - Aura
Enchant creature, land, or planeswalker
Enchanted permanent is a colorless land with "{T}: Add {C}" and loses all other card types and abilities.
{1}{U}
Impulse
Instant
Look at the top four cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.
{0}
Jeweled Lotus
Artifact
{T}, Sacrifice Jeweled Lotus: Add three mana of any one color. Spend this mana only to cast your commander.
{2}{U}
Jwari Scuttler
Creature - Crab
2 /
3
{1}{U}
Kasmina's Transmutation
Enchantment - Aura
Enchant creature
Enchanted creature loses all abilities and has base power and toughness 1/1.
{3}{U}
Kasmina, Enigmatic Mentor
Legendary Planeswalker - Kasmina
Spells your opponents cast that target a creature or planeswalker you control cost {2} more to cast.
-2: Create a 2/2 blue Wizard creature token. Draw a card, then discard a card.
L:
5
{3}
Kefnet's Monument
Legendary Artifact
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.
--
Lonely Sandbar
Land
Lonely Sandbar enters the battlefield tapped.
{T}: Add {U}.
Cycling {U} ({U}, Discard this card: Draw a card.)
{1}
Masterwork of Ingenuity
Artifact - Equipment
You may have Masterwork of Ingenuity enter the battlefield as a copy of any Equipment on the battlefield.
--
Misty Rainforest
Land
{T}, Pay 1 life, Sacrifice Misty Rainforest: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.
{2}{U}
Monastery Siege
Enchantment
As Monastery Siege enters the battlefield, choose Khans or Dragons.
• Khans -- At the beginning of your draw step, draw an additional card, then discard a card.
• Dragons -- Spells your opponents cast that target you or a permanent you control cost {2} more to cast.
{1}{U}{U}
Mu Yanling, Sky Dancer
Legendary Planeswalker - Yanling
+2: Until your next turn, up to one target creature gets -2/-0 and loses flying.
-3: Create a 4/4 blue Elemental Bird creature token with flying.
-8: You get an emblem with "Islands you control have '{T}: Draw a card.'"
L:
2
{4}{U}
Mulldrifter
Creature - Elemental
Flying
When Mulldrifter enters the battlefield, draw two cards.
Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters the battlefield.)
2 /
2
--
Myriad Landscape
Land
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.
{3}{U}{U}
Mystic Confluence
Instant
Choose three. You may choose the same mode more than once.
• Counter target spell unless its controller pays {3}.
• Return target creature to its owner's hand.
• Draw a card.
--
Nykthos, Shrine to Nyx
Legendary Land
{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)
{1}{U}
Omen of the Sea
Enchantment
Flash
When Omen of the Sea enters the battlefield, scry 2, then draw a card.
{2}{U}, Sacrifice Omen of the Sea: Scry 2.
--
Polluted Delta
Land
{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.
{U}
Ponder
Sorcery
Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.
{U}
Preordain
Sorcery
Scry 2, then draw a card. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)
{1}{U}
Purple-Crystal Crab
Creature - Crab
When Purple-Crystal Crab dies, draw a card.
1 /
1
{3}
Quietus Spike
Artifact - Equipment
Equipped creature has deathtouch.
Whenever equipped creature deals combat damage to a player, that player loses half their life, rounded up.
Equip {3}
{4}{U}
Reflections of Littjara
Enchantment
As Reflections of Littjara enters the battlefield, 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.)
--
Remote Isle
Land
Remote Isle enters the battlefield tapped.
{T}: Add {U}.
Cycling {2} ({2}, Discard this card: Draw a card.)
{2}{U}{U}
Rite of Replication
Sorcery
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.
--
Rogue's Passage
Land
{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.
{U}
Ruin Crab
Creature - Crab
Landfall -- Whenever a land enters the battlefield under your control, each opponent mills three cards. (To mill a card, a player puts the top card of their library into their graveyard.)
0 /
3
{3}{U}
Sakashima of a Thousand Faces
Legendary Creature - Human Rogue
You may have Sakashima of a Thousand Faces enter the battlefield as a copy of another creature you control, except it has Sakashima of a Thousand Faces's other abilities.
The "legend rule" doesn't apply to permanents you control.
Partner (You can have two commanders if both have partner.)
3 /
1
{2}{U}{U}
Sakashima the Impostor
Legendary Creature - Human Rogue
You may have Sakashima the Impostor enter the battlefield as a copy of any creature on the battlefield, except its name is Sakashima the Impostor, it's legendary in addition to its other types, and it has "{2}{U}{U}: Return this creature to its owner's hand at the beginning of the next end step."
3 /
1
{2}
Sapphire Medallion
Artifact
Blue spells you cast cost {1} less to cast.
--
Scalding Tarn
Land
{T}, Pay 1 life, Sacrifice Scalding Tarn: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.
{1}
Shadowspear
Legendary Artifact - Equipment
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}
{3}{U}
Skitter Eel
Creature - Fish Crab
{2}{U}: Adapt 2. (If this creature has no +1/+1 counters on it, put two +1/+1 counters on it.)
3 /
3
{2}{U}
Skittering Crustacean
Creature - Crab
{6}{U}: Monstrosity 4. (If this creature isn't monstrous, put four +1/+1 counters on it and it becomes monstrous.)
As long as Skittering Crustacean is monstrous, it has hexproof. (It can't be the target of spells or abilities your opponents control.)
2 /
3
{2}
Sky Diamond
Artifact
Sky Diamond enters the battlefield tapped.
{T}: Add {U}.
--
Skyline Cascade
Land
Skyline Cascade enters the battlefield tapped.
When Skyline Cascade enters the battlefield, target creature an opponent controls doesn't untap during its controller's next untap step.
{T}: Add {U}.
--
Snow-Covered Island
Basic Snow Land - Island
({T}: Add {U}.)
--
Snow-Covered Island
Basic Snow Land - Island
({T}: Add {U}.)
--
Snow-Covered Island
Basic Snow Land - Island
({T}: Add {U}.)
--
Snow-Covered Island
Basic Snow Land - Island
({T}: Add {U}.)
--
Snow-Covered Island
Basic Snow Land - Island
({T}: Add {U}.)
--
Snow-Covered Island
Basic Snow Land - Island
({T}: Add {U}.)
--
Snow-Covered Island
Basic Snow Land - Island
({T}: Add {U}.)
--
Snow-Covered Island
Basic Snow Land - Island
({T}: Add {U}.)
--
Snow-Covered Island
Basic Snow Land - Island
({T}: Add {U}.)
--
Snow-Covered Island
Basic Snow Land - Island
({T}: Add {U}.)
--
Snow-Covered Island
Basic Snow Land - Island
({T}: Add {U}.)
--
Snow-Covered Island
Basic Snow Land - Island
({T}: Add {U}.)
--
Snow-Covered Island
Basic Snow Land - Island
({T}: Add {U}.)
--
Snow-Covered Island
Basic Snow Land - Island
({T}: Add {U}.)
--
Snow-Covered Island
Basic Snow Land - Island
({T}: Add {U}.)
--
Snow-Covered Island
Basic Snow Land - Island
({T}: Add {U}.)
--
Soaring Seacliff
Land
Soaring Seacliff enters the battlefield tapped.
When Soaring Seacliff enters the battlefield, target creature gains flying until end of turn.
{T}: Add {U}.
{1}
Sol Ring
Artifact
{T}: Add {C}{C}.
{4}
Solemn Simulacrum
Artifact Creature - Golem
When Solemn Simulacrum enters the battlefield, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When Solemn Simulacrum dies, you may draw a card.
2 /
2
{3}{U}
Spark Double
Creature - Illusion
You may have Spark Double enter the battlefield as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.
0 /
0
{4}{U}{U}
Stolen Identity
Sorcery
Create a token that's a copy of target artifact or creature.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)
{1}
Stoneforge Masterwork
Artifact - Equipment
Equipped creature gets +1/+1 for each other creature you control that shares a creature type with it.
Equip {2}
{1}{U}
Telling Time
Instant
Look at the top three cards of your library. Put one of those cards into your hand, one on top of your library, and one on the bottom of your library.
--
Terramorphic Expanse
Land
{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
{3}{U}
Thassa's Emissary
Enchantment Creature - Crab
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 Thassa's Emissary or enchanted creature deals combat damage to a player, draw a card.
Enchanted creature gets +3/+3.
3 /
3
{2}{U}
Thassa, God of the Sea
Legendary Enchantment Creature - God
Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)
At the beginning of your upkeep, scry 1.
{1}{U}: Target creature you control can't be blocked this turn.
5 /
5
{U}
Unsummon
Instant
Return target creature to its owner's hand.
{8}
Vexing Scuttler
Creature - Eldrazi Crab
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.
4 /
5
{3}{U}
Wash Out
Sorcery
Return all permanents of the color of your choice to their owners' hands.
{3}{U}
Wishcoin Crab
Creature - Crab
2 /
5
{3}{U}
Wonder
Creature - Incarnation
Flying
As long as Wonder is in your graveyard and you control an Island, creatures you control have flying.