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}.

Gitaxian Probe

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

Counterspell

Dismember

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

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.)

Disperse

Return target nonland permanent to its owner's hand.

Mox Sapphire

Spell Pierce

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

Tropical Island

Triton Shorestalker

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.)

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.)

Censor

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

Lord of Atlantis

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

Merfolk Mistbinder

Island

Mox Emerald

Forest

Blue Elemental Blast

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

Tidal Warrior

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