msem-instigator

Haste
When Jetskate enters the battlefield, if you've drawn two or more cards this turn, it deals 2 damage to any target.
Cycling {R} ({R}, Discard this card: Draw a card.)

This spell costs {1} less to cast for each spell you cast this turn.
When Jidai Serpent enters the battlefield, draw two cards.

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.)

When Jumbo Shrimp enters the battlefield or when you cycle it, destroy target noncreature permanent.
Cycling {3}{G}{G} ({3}{G}{G}, Discard this card: Draw a card.)

Whenever a creature attacks you or a planeswalker you control, put that creature on the bottom of its owner's library unless its controller pays {2}.

Flash
When Kaivilu, Ocean Warden enters the battlefield, creatures your opponents control get -2/-2 and lose all abilities until end of turn.

{1}{G}: Keen Seafarer voyages. (If it isn't blocking or targeted by another spell or ability, it phases out.)
Whenever Keen Seafarer phases in, put a +1/+1 counter on it.

When Keeper of Pearls enters the battlefield or a creature scavenges it, you gain 2 life.
Scavenge {G} ({G}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

Creatures you control get +1/+0 for each color among permanents you control and have haste.
Whenever you cast a white, blue, black, or green instant or sorcery spell, copy it for each of its colors. You may choose new targets for the copies.

Concord — You may cast this spell as though it had flash if there are four or more card types among permanents you control.
When Krill-Clan Guardian enters the battlefield, it fights up to one other target creature. If that creature would die this turn, return it to its owner's hand instead.

{T}: Target land you control becomes the basic land type of your choice until end of turn.
At the beginning of each end step, if you spent three or more colors of mana to cast spells this turn, surveil 1.

({T}: Add {W} or {U}.)
As Lakeside Park enters the battlefield, you may pay {1}. If you don't, Lakeside Park enters the battlefield tapped.

Whenever you cast a spell during another player's turn, monstrosity 1. (If this creature isn't monstrous, put a +1/+1 counter on it and it becomes monstrous.)

Kindle 4—{4}{U}{U} ({4}{U}{U}, Exile this card from your graveyard: Create four 1/1 colorless Elemental creature tokens. Kindle only as a sorcery.)

Haste
You may cast sorcery and enchantment spells as though they had flash.
Whenever you cast an enchantment, instant, or sorcery spell, Lightning-Fast Lionfish gets +1/+0 and gains first strike until end of turn.

When Lilyreed Triton enters the battlefield, 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.”

When Lionfrill Hunter enters the battlefield or when you cycle it, put X +1/+1 counters on another target creature you control, where X is the number of cards with a cycling ability in your graveyard.
Cycling {3}{R}{G} ({3}{R}{G}, Discard this card: Draw a card.)

Trample
Whenever Living Archipelago enters the battlefield or attacks, up to two target lands you control voyage. (If they aren't being targeted by another spell or ability, they phase out.)
Whenever a land you control phases in, you may create a tapped token that's a copy of that land.

Flying
Long-Finned Skywhale can block only creatures with flying.

Other Merfolk you control get +1/+1.
{1}{U}: Target Merfolk gains slipstream until end of turn. (Creatures with slipstream can't be blocked as long as only creatures with slipstream are attacking.)

Lumbering Stoneshell has hexproof as long as it's untapped.

When Lurking Angler enters the battlefield, if seven or more cards are in your graveyard, draw a card. Otherwise, mill two cards.

({T}: Add {G} or {U}.)
Lush Oasis enters the battlefield tapped unless you control a basic Forest or a basic Island.

Attacking Pirates and Rogues you control get +1/+0.
{2}{U}: Tap target creature an opponent controls.

First mate—Each nonland card in your starting deck is an instant or has flash. (If this card outside the game is your chosen first mate, you may swap it with a card in your opening hand.)
Flash
When Mable enters the battlefield, you gain 2 life and draw a card.