msem-instigator

Counter target spell unless its controller pays {X}. Scry 2.

As an additional cost to cast this spell, return a creature you control to its owner's hand or pay {2}.
Counter target spell.

When Helicos Octopus enters, scry 1. If an opponent is cursed, scry 3 instead.

The next creature spell you cast this turn can be cast as though it had flash. When that creature enters this turn, it gains lifelink until end of turn.

{X}{U}{U}: Marine Monster can't be blocked by creatures with mana value X or less this turn.

Whenever a Survivor you control enters, look at the top card of target opponent's library. You may have them put that card into their graveyard.

Whenever Skeigr, Skhorvall Flagship attacks, it deals 3 damage divided as you choose among one, two, or three targets.
Crew 3 (Tap any number of creatures you control with total power 3 or greater: This Ship Vehicle becomes an artifact creature until end of turn.)

When Silverhorn Tactician enters, permutate. (You may remove a counter from a creature you control. If you do, put two +1/+1 counters on a different creature you control.)

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
Whenever Knight of the Cockatrice attacks, you may pay {1}{R}. When you do, target creature can't block this turn.

Trample
Whenever Arisen Tyrant attacks, mill three cards, then you may exile a card from your graveyard. You may cast a copy of the exiled card without paying its mana cost if the spell's mana value is 3 or less.
If Arisen Tyrant would die, exile it instead.

Destroy target artifact or enchantment with mana value 3 or less.
Ferocious — You gain 4 life if you control a creature with power 4 or greater.

Outlands Bodyguard can't attack alone.
You may exert Outlands Bodyguard as it attacks. When you do, it must be blocked this turn if able. (An exerted creature won't untap during your next untap step.)

When Monstrous Hunter enters, destroy up to one target creature.
At the beginning of each end step, if a creature died this turn, you draw a card and you lose 1 life.

Destroy target creature with flying. (Then exile this card. You may cast the creature later from exile.)

Destroy target enchantment. Put a +1/+1 counter on target creature you control.

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 Callous Renegade enters, you may return target Rebel creature card with mana value 4 or less from your graveyard to the battlefield. It gains haste until end of turn.

Assault {1}{R} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
When Urudi Warlord assaults, it gains first strike until end of turn.

When Greedy Insects enters, exile up to one target artifact or enchantment until Greedy Insects leaves the battlefield.

You gain 2 life and draw two cards.

At the beginning of your upkeep, if there are no noncreature cards in your graveyard, you may return target creature card from your graveyard to the battlefield.

{T}: Create a Treasure token.
{W}{U}{B}{R}{G}: Until end of turn, Guardians of Kallian's Tomb becomes a 5/5 Ox artifact creature and gains trample and “Whenever this creature attacks, defending player sacrifices a permanent unless they have you draw two cards.”

Exile cards from the top of your library until you exile a nonland card. You may play one of those cards from exile until the end of your next turn.

Destroy target creature if it has the least power or is tied for least power among creatures on the battlefield.
Memento {3}{B}{B} (You may cast this from your graveyard for {3}{B}{B}. If you do, put it onto the battlefield transformed after it resolves. Exile it if it would leave the battlefield or not resolve.)

Menace
Other artifact creatures you control have menace.
{2}{B}{R}: Salvage an artifact or creature card. (Exile one from your graveyard until this creature leaves the battlefield. Whenever this creature deals combat damage to a player, put a card it salvaged into your hand.)