msem-instigator

Choose one —
• Target creature gains indestructible until end of turn.
• Destroy target creature with toughness 4 or greater.

Deathtouch
Poisoned Aleud must be blocked if able.

Flying, trample
Whenever Bretala of Redsky attacks, it gains double strike until end of turn unless defending player sacrifices a creature.

Other Merfolk you control get +1/+1.
When Olantin Pearlreader enters, scry 2. Then draw a card if you control two or more other Merfolk.

Whenever a spell or ability causes an opponent to draw a card, draw a card unless that player pays 1 life.

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
When Cauldish Cavalier becomes renowned, you may pay 2 life. If you do, draw two cards.

Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{4}{G}: Target creature gets +2/+2 until end of turn.

This spell costs {1} less to cast if you have more life than an opponent and {1} less to cast if you control a Cleric.
Deathtouch

Choose a creature. When it dies this turn, distribute two +1/+1 counters among any number of creatures you control.

When this creature enters, you may return another target creature you control to its owner's hand. If you do, create a Treasure token.

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.)

Vigilance, trample
When Threshold Guardian enters, return a creature you control to its owner's hand.

Enchant creature you control
When Nylea's Benefaction enters, scry 2.
Enchanted creature gets +3/+3 and has reach.

Flying, first strike
Whenever this creature transforms into Flame-Tested Dragon or attacks, it deals 1 damage to each creature you don't control.

Crossfire deals 1 damage to each creature.
Quickdraw {2}{R} (When a creature you control blocks or becomes blocked, you may cast this spell for {2}{R}.)

As an additional cost to cast this spell, tap an untapped Warlock you control.
Search your library for a card and put it into your hand or graveyard, then shuffle.

Flash (You may cast this spell any time you could cast an instant.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

You may reveal any number of creature cards you own from outside the game with the same name and put them into your hand. Exile Cosmic Lineage.

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
When Kantra of Old Majik enters, you may return target card from your graveyard to your hand.

Equipped creature gets +2/+2 and has protection from mana value 2 or less and from mana value 6 or greater.
Whenever equipped creature deals combat damage to a player, create a Food token and two Treasure tokens.
Equip {2}

Erosive Path enters tapped unless you control one or fewer other lands.
{T}: Add {B} or {R}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Flash
When Cephalovorous Flukes enters, counter target spell or ability that targets you or a permanent you control.

Enchant creature
Enchanted creature gets +1/+1.
When enchanted creature dies, return another target creature card from your graveyard to your hand.

Colorless creatures you control have “{T}: Add {C}.”

Whenever Sage of Reflections attacks, mill three cards, then choose a creature card milled this way. Create a token that's a copy of it that's tapped and attacking, except it has no mana cost.