Lord of Atlantis

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

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Recall

Discard X cards, then return a card from your graveyard to your hand for each card discarded this way. Exile Recall.

Mahamoti Djinn

Flying (This creature can't be blocked except by creatures with flying or reach.)

Prodigal Sorcerer

{T}: Prodigal Sorcerer deals 1 damage to any target.

Spell Blast

Counter target spell with mana value X. (For example, if that spell's mana cost is {3}{U}{U}, X is 5.)

Merfolk of the Pearl Trident

Serendib Efreet

Flying
At the beginning of your upkeep, Serendib Efreet deals 1 damage to you.

Phantasmal Terrain

Enchant land
As Phantasmal Terrain enters, choose a basic land type.
Enchanted land is the chosen type.

Braingeyser

Timetwister

Each player shuffles their hand and graveyard into their library, then draws seven cards. (Then put Timetwister into its owner's graveyard.)

Ancestral Recall

Black Lotus

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

Counterspell

Unstable Mutation

Enchant creature
Enchanted creature gets +3/+3.
At the beginning of the upkeep of enchanted creature's controller, put a -1/-1 counter on that creature.

Blue Elemental Blast

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

Mishra's Factory

{T}: Add {C}.
{1}: Mishra's Factory becomes a 2/2 Assembly-Worker artifact creature until end of turn. It's still a land.
{T}: Target Assembly-Worker creature gets +1/+1 until end of turn.

Mox Sapphire

Boomerang

Return target permanent to its owner's hand.

Energy Flux

All artifacts have "At the beginning of your upkeep, sacrifice this artifact unless you pay {2}."

Unsummon

Return target creature to its owner's hand.

Island

Clone

You may have Clone enter as a copy of any creature on the battlefield.

Hurkyl's Recall

Return all artifacts target player owns to their hand.

Dandân

Dandân can't attack unless defending player controls an Island.
When you control no Islands, sacrifice Dandân.