Hibernation

Return all green permanents to their owners' hands.

Blind Seer

{1}{U}: Target spell or permanent becomes the color of your choice until end of turn.

Douse

Tidebinder Mage

When Tidebinder Mage enters, tap target red or green creature an opponent controls. That creature doesn't untap during its controller's untap step for as long as you control Tidebinder Mage.

Vodalian Mystic

{T}: Target instant or sorcery spell becomes the color of your choice.

Hydroblast

Choose one —
• Counter target spell if it's red.
• Destroy target permanent if it's red.

Scuttlemutt

{T}: Add one mana of any color.
{T}: Target creature becomes the color or colors of your choice until end of turn.

Shifting Sky

As Shifting Sky enters, choose a color.
All nonland permanents are the chosen color.

Heartstone

Activated abilities of creatures cost {1} less to activate. This effect can't reduce the mana in that cost to less than one mana.

High Tide

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

Omen Hawker

{T}: Add {C}{U}. Spend this mana only to activate abilities.

Harbinger of the Seas

Insight

Whenever an opponent casts a green spell, you draw a card.

Chameleon Spirit

As Chameleon Spirit enters, choose a color.
Chameleon Spirit's power and toughness are each equal to the number of permanents of the chosen color your opponents control.

Tidal Visionary

{T}: Target creature becomes the color of your choice until end of turn.

Wash Out

Return all permanents of the color of your choice to their owners' hands.

Dismiss into Dream

Each creature your opponents control is an Illusion in addition to its other types and has "When this creature becomes the target of a spell or ability, sacrifice it."

Flash Flood

Choose one —
• Destroy target red permanent.
• Return target Mountain to its owner's hand.

Llawan, Cephalid Empress

When Llawan, Cephalid Empress enters, return all blue creatures your opponents control to their owners' hands.
Your opponents can't cast blue creature spells.

Cowardice

Whenever a creature becomes the target of a spell or ability, return that creature to its owner's hand. (It won't be affected by the spell or ability.)

Blue Elemental Blast

Choose one —
• Counter target red spell.
• Destroy target red permanent.

Defiler of Dreams

Flying
As an additional cost to cast blue permanent spells, you may pay 2 life. Those spells cost {U} less to cast if you paid life this way. This effect reduces only the amount of blue mana you pay.
Whenever you cast a blue permanent spell, draw a card.

Willbreaker

Whenever a creature an opponent controls becomes the target of a spell or ability you control, gain control of that creature for as long as you control Willbreaker.

Eluge, the Shoreless Sea

Eluge's power and toughness are each equal to the number of Islands you control.
Whenever Eluge enters or attacks, put a flood counter on target land. It's an Island in addition to its other types for as long as it has a flood counter on it.
The first instant or sorcery spell you cast each turn costs {U} (or {1}) less to cast for each land you control with a flood counter on it.

Sway of Illusion

Any number of target creatures become the color of your choice until end of turn.
Draw a card.

Distorting Lens

{T}: Target permanent becomes the color of your choice until end of turn.

Well-Laid Plans

Prevent all damage that would be dealt to a creature by another creature if they share a color.