Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

Preordain

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.)

Forest

Mox Sapphire

Triton Shorestalker

Disperse

Return target nonland permanent to its owner's hand.

Island

Dismember

({B/P} can be paid with either {B} or 2 life.)
Target creature gets -5/-5 until end of turn.

Gitaxian Probe

({U/P} can be paid with either {U} or 2 life.)
Look at target player's hand.
Draw a card.

Mox Emerald

Counterspell

Tidal Warrior

{T}: Target land becomes an Island until end of turn.

Tropical Island

Lord of Atlantis

Other Merfolk get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)

Censor

Counter target spell unless its controller pays {1}.
Cycling {U} ({U}, Discard this card: Draw a card.)

Blue Elemental Blast

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

Black Lotus

{T}, Sacrifice Black Lotus: Add three mana of any one color.

Vodalian Mage

{U}, {T}: Counter target spell unless its controller pays {1}.

Lórien Revealed

Draw three cards.
Islandcycling {1} ({1}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

Merfolk Mistbinder

Wear Away

Destroy target artifact or enchantment.
Splice onto Arcane {3}{G} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)