Blood Moon

Psychic Purge

Psychic Purge deals 1 damage to any target.
When a spell or ability an opponent controls causes you to discard Psychic Purge, that player loses 5 life.

Counterspell

Island

Volcanic Island

River Merfolk

{U}: River Merfolk gains mountainwalk until end of turn. (It can't be blocked as long as defending player controls a Mountain.)

Energy Flux

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

Time Walk

Unsummon

Return target creature to its owner's hand.

Flying Men

Falling Star

Flip Falling Star onto the playing area from a height of at least one foot. Falling Star deals 3 damage to each creature it lands on. Tap all creatures dealt damage by Falling Star. If Falling Star doesn't turn completely over at least once during the flip, it has no effect.

Serendib Efreet

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

Lord of Atlantis

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

Desert

{T}: Add {C}.
{T}: Desert deals 1 damage to target attacking creature. Activate only during the end of combat step.

Aeolipile

{1}, {T}, Sacrifice Aeolipile: It deals 2 damage to any target.

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.

Ancestral Recall

Force Spike

Counter target spell unless its controller pays {1}.

Psionic Blast

Psionic Blast deals 4 damage to any target and 2 damage to you.

Pendelhaven

{T}: Add {G}.
{T}: Target 1/1 creature gets +1/+2 until end of turn.

Merfolk of the Pearl Trident

Strip Mine

{T}: Add {C}.
{T}, Sacrifice Strip Mine: Destroy target land.

Chaos Orb

{1}, {T}: If Chaos Orb is on the battlefield, flip Chaos Orb onto the battlefield from a height of at least one foot. If Chaos Orb turns over completely at least once during the flip, destroy all nontoken permanents it touches. Then destroy Chaos Orb.