Misleading Signpost

Flash
When this artifact enters during the declare attackers step, you may reselect which player or permanent target attacking creature is attacking. (It can't attack its controller or their permanents.)
{T}: Add {U}.

Hellish Rebuke

Until end of turn, permanents your opponents control gain "When this permanent deals damage to the player who cast Hellish Rebuke, sacrifice this permanent. You lose 2 life."

Norritt

{T}: Untap target blue creature.
{T}: Choose target non-Wall creature the active player has controlled continuously since the beginning of the turn. That creature attacks this turn if able. Destroy it at the beginning of the next end step if it didn't attack this turn. Activate only before attackers are declared.

Keep Watch

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Path of Ancestry

This land enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

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.

Dimir Signet

Hypnotic Siren

Bestow {5}{U}{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.)
Flying
You control enchanted creature.
Enchanted creature gets +1/+1 and has flying.

Mistral Singer

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Siren Lookout

Flying
When this creature enters, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

Alluring Siren

{T}: Target creature an opponent controls attacks you this turn if able.

Aetherize

Return all attacking creatures to their owner's hand.

Fellwar Stone

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

Taunt

During target player's next turn, creatures that player controls attack you if able.

Reconnaissance Mission

Whenever a creature you control deals combat damage to a player, you may draw a card.
Cycling {2} ({2}, Discard this card: Draw a card.)

Shipwreck Marsh

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

Command Tower

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

Dreamcaller Siren

Flash
Flying
This creature can block only creatures with flying.
When this creature enters, if you control another Pirate, tap up to two target nonland permanents.

Maeve, Insidious Singer

{2}{U}: Goad target creature. Whenever that creature attacks one of your opponents this turn, you draw a card. (A goaded creature attacks each combat if able and attacks a player other than you if able, until your next turn.)

Ever-Watching Threshold

Whenever an opponent attacks, if they attacked you and/or a planeswalker you control, draw a card.

Public Enemy

Enchant creature
All creatures attack enchanted creature's controller each combat if able.
When enchanted creature dies, draw a card.

Tainted Isle

{T}: Add {C}.
{T}: Add {U} or {B}. Activate only if you control a Swamp.

Malcolm, Alluring Scoundrel

Flash
Flying
Whenever Malcolm deals combat damage to a player, put a chorus counter on it. Draw a card, then discard a card. If there are four or more chorus counters on Malcolm, you may cast the discarded card without paying its mana cost.

Siren Stormtamer

Flying
{U}, Sacrifice this creature: Counter target spell or ability that targets you or a creature you control.

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Changeling Outcast

Changeling (This card is every creature type.)
This creature can't block and can't be blocked.

Choked Estuary

As this land enters, you may reveal an Island or Swamp card from your hand. If you don't, this land enters tapped.
{T}: Add {U} or {B}.

Drowned Catacomb

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

Withering Torment

Destroy target creature or enchantment. You lose 2 life.

Storm Fleet Negotiator

Flying
Parley — Whenever this creature attacks, each player reveals the top card of their library. For each nonland card revealed this way, you create a Map token. Then each player draws a card. (A Map token is an artifact with "{1}, {T}, Sacrifice this token: Target creature you control explores. Activate only as a sorcery.")

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. This artifact deals 1 damage to you.

Swamp

Imaginary Threats

Creatures target opponent controls attack this turn if able. During that player's next untap step, creatures they control don't untap.
Cycling {2} ({2}, Discard this card: Draw a card.)

Siren's Call

Cast this spell only during an opponent's turn, before attackers are declared.
Creatures the active player controls attack this turn if able.
At the beginning of the next end step, destroy all non-Wall creatures that player controls that didn't attack this turn. Ignore this effect for each creature the player didn't control continuously since the beginning of the turn.

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.

Bojuka Bog

This land enters tapped.
When this land enters, exile target player's graveyard.
{T}: Add {B}.

Spyglass Siren

Flying
When this creature enters, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this token: Target creature you control explores. Activate only as a sorcery.")

Abjure

As an additional cost to cast this spell, sacrifice a blue permanent.
Counter target spell.

Hydroelectric Laboratory

As this land enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {U}.

Hydroelectric Specimen

Flash
When this creature enters, you may change the target of target instant or sorcery spell with a single target to this creature.

Hydroelectric Specimen // Hydroelectric Laboratory

Domineering Will

Target player gains control of up to three target nonattacking creatures until end of turn. Untap those creatures. They block this turn if able.

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.

Dimir Aqueduct

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

Cunning Rhetoric

Whenever an opponent attacks you and/or one or more planeswalkers you control, exile the top card of that player's library. You may play that card for as long as it remains exiled, and you may spend mana as though it were mana of any color to cast it.

Rapid Hybridization

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

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.

Dulcet Sirens

{U}, {T}: Target creature attacks target opponent this turn if able.
Morph {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.)

Sol Ring

Black Market Connections

At the beginning of your first main phase, choose one or more —
• Sell Contraband — Create a Treasure token. You lose 1 life.
• Buy Information — Draw a card. You lose 2 life.
• Hire a Mercenary — Create a 3/2 colorless Shapeshifter creature token with changeling. You lose 3 life. (It is every creature type.)

Kindred Dominance

Choose a creature type. Destroy all creatures that aren't of the chosen type.

Shipwreck Singer

Flying
{1}{U}: Target creature an opponent controls attacks this turn if able.
{1}{B}, {T}: Attacking creatures get -1/-1 until end of turn.

Underground River

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

No Mercy

Whenever a creature deals damage to you, destroy it.

Dissipation Field

Whenever a permanent deals damage to you, return it to its owner's hand.

Arcane Signet

Angler Turtle

Hexproof
Creatures your opponents control attack each combat if able.

Siren Reaver

Raid — This spell costs {1} less to cast if you attacked this turn.
Flying

Siren of the Fanged Coast

Flying
Tribute 3 (As this creature enters, an opponent of your choice may put three +1/+1 counters on it.)
When this creature enters, if tribute wasn't paid, gain control of target creature.

Island

Reliquary Tower

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

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.

Pursued Whale

When this creature enters, each opponent creates a 1/1 red Pirate creature token with "This token can't block" and "Creatures you control attack each combat if able."
Spells your opponents cast that target this creature cost {3} more to cast.

Sign in Blood

Target player draws two cards and loses 2 life.

Cloaked Siren

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

Sunken Hollow

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

Trench Behemoth

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

Counterspell

Distant Melody

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

Countersquall

Counter target noncreature spell. Its controller loses 2 life.

Negate

Patchwork Banner

As this artifact enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{T}: Add one mana of any color.

Courtly Provocateur

{T}: Target creature attacks this turn if able.
{T}: Target creature blocks this turn if able.