msem-instigator

Concord — Whenever Bubbledome Captain attacks, if there are four or more card types among permanents you control, each other attacking creature gets +1/+1 until end of turn.

Flash
When Cast Out enters, exile target nonland permanent an opponent controls until Cast Out leaves the battlefield.
Cycling {W} ({W}, Discard this card: Draw a card.)

Concord — Whenever Chitinborn Sentry attacks, if there are four or more card types among permanents you control, prevent all damage that would be dealt to target attacking creature this turn.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Whenever Conchhorn Shinygrabber attacks, you may pay {1}. If you do, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
{W}{U}{B}{R}{G}: Conchhorn Shinygrabber gets +3/+3 and gains lifelink until end of turn.

Exile target creature with power 4 or greater.
Create a Treasure token. (It's an artifact with “{T}, Sacrifice this permanent: Add one mana of any color.”)

When Coralight Champion enters, create a white Aura enchantment token named Hila's Favor attached to target creature. The token has enchant creature and “Enchanted creature has double strike as long as there's another Aura attached to it. Otherwise, it has first strike.”

{3}{W}: Tap target creature. Activate only during your turn.

When Coralight Mystic enters, create a white Aura enchantment token named Whale's Spirit attached to target creature. The token has enchant creature and “Enchanted creature has lifelink.”

Vigilance
When Coralight Sentinel enters, create a white Aura enchantment token named Crab's Resolve attached to target creature. The token has enchant creature and “Enchanted creature gets +0/+2.”

When Dawson's Bouncer enters, choose one —
• Put a +1/+1 counter on Dawson's Bouncer.
• Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Creatures you control get +1/+1 until end of turn. Merfolk you control get an additional +1/+1 until end of turn.

Vigilance
Whenever an opponent casts a spell, create a Treasure token unless that player pays {1}, then create a 1/1 white Merfolk creature token unless that player pays {1}.
{W}{U}{B}{R}{G}, {T}: Other creatures you control get +3/+3 and gain vigilance and indestructible until end of turn.

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)

When Gilded Merrow enters, if an opponent controls more lands than you, create a Treasure token. (It's an artifact with “{T}, Sacrifice this permanent: Add one mana of any color.”)

Vigilance
Whenever Glittering Narwhal is dealt damage, create a Treasure token. (It's an artifact with “{T}, Sacrifice this permanent: Add one mana of any color.”)

Enchant creature
Enchanted creature gets +2/+2.
Concord — As long as there are four or more card types among permanents you control, enchanted creature has slipstream. (This creature can't be blocked as long as only creatures with slipstream are attacking.)

Concord — At the beginning of your upkeep, if there are four or more card types among permanents you control, you gain 1 life and create a 1/1 blue Jellyfish enchantment creature token with slipstream. (It can't be blocked as long as only creatures with slipstream are attacking.)

Concord — This spell costs {2} less to cast if there are four or more card types among permanents you control.
Vigilance (Attacking doesn't cause this creature to tap.)

Exile target creature if its controller controls more lands than you.
Cycling {2} ({2}, Discard this card: Draw a card.)

Exile all creatures, then for each creature exiled this way, you may return it to the battlefield under its owner's control. For each creature you didn't return to the battlefield this way, its owner may search their library for a basic land card and put it onto the battlefield tapped. Each player that does shuffles.

When Lilyreed Triton enters, create a white Aura enchantment token named Triton's Gift attached to target creature. The token has enchant creature and “Enchanted creature gets +1/+0 and can't be blocked by creatures with power 3 or greater.”

Majestic Nauticorn has first strike as long as it's attacking.
Cycling {W} ({W}, Discard this card: Draw a card.)

Whenever Merrow Legendmaker attacks, look at the top five cards of your library. You may reveal an Aura, Aurashaper, or Equipment card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

When Militant's Standard enters, draw a card if you control a Merfolk.
Equipped creature gets +2/+1.
Equip {2}

Choose one —
• Return target artifact or enchantment card from your graveyard to your hand.
• Return target creature card with mana value 2 or less from your graveyard to your hand.
Cycling {2} ({2}, Discard this card: Draw a card.)