msem-instigator

Counter target spell. If that spell is countered this way, until the end of your next turn the next spell you cast that shares a type with it costs {X} less to cast, where X is the countered spell's mana value.

Flash
When Icecrowned Fox enters, you may return target spell or permanent to its owner's hand.
Each untapped creature you control has “Ward—Discard a card.” (Whenever it becomes the target of a spell or ability an opponent controls, counter it unless that player discards a card.)

Haste
Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Spend only mana produced by artifacts to cast Dawson's Jetslicer.

When Paul's Finest Act enters, search your library for a legendary red card, reveal it, put it into your hand, then shuffle.
Creatures you control get +1/+0 as long as you've cast a noncreature spell this turn.

Whenever Scaleblight Cutthroat attacks, each opponent loses life equal to its power.
{4}{B}{B}: Scaleblight Cutthroat gets +3/+3 until end of turn.

Menace, haste
Invocation — Whenever you spend four or more mana to cast a spell or activate an ability during your turn, return Deathless Butcher from your graveyard to your hand.

When Citywide Automation enters, create two 1/1 colorless Construct artifact creature tokens.
{2}{W}{W}, Sacrifice Citywide Automation: Creatures you control get +1/+1 until end of turn. Activate only as a sorcery.

Whenever you sacrifice a permanent, you may put a soul counter on Soul's Guidestone.
As long as there are five or more soul counters on Soul's Guidestone, it's a 6/6 Golem artifact creature with menace and vigilance.

Finale of Cinders deals 2 damage to any target. For each instant and sorcery card in your graveyard, you may pay {R}. Whenever you do, Finale of Cinders deals 2 damage to any target.

When Bearer of Silk Chains enters, gain control of target nonland permanent until Bearer of Silk Chains leaves the battlefield. If that permanent is a Horror, gain control of it instead.

When Marshal of Brethren enters, amass Soldiers 1. (Put a +1/+1 counter on an Army you control. It's also a Soldier. If you don't control one, create an 0/0 black Soldier Army creature token first.)

Menace
Whenever Despair Scavenger attacks, you may have target creature get -1/-1 until end of turn.

Haste
This creature can't block.
{2}{R}: Return this card from your graveyard to your hand.

Flying
Desecrate (When this creature enters, you may sacrifice an artifact or land.)
When Liege of Luxury desecrates a permanent, target player reveals their hand. You choose a card from it and exile it. You may cast that card for as long as it remains exiled, and you may spend mana as though it were mana of any type to cast that spell.

As an additional cost to cast this spell, discard a card.
Create three 1/1 red Soldier creature tokens with haste.

Crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)
Voice of the Universe deals 2 damage to each creature.

Rei, the Supplanter gets +1/+1 for each Forest you control.
At the beginning of each player's end step, if that player didn't play a land this turn, create a Forest token.

Vigilance
{7}{G}: Molting Linnorm gets +5/+5 and gains trample until end of turn.

Target creature gets +2/+1 until end of turn. (Then exile this card. You may cast the creature later from exile.)

Haste
Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)

{1}{U}: Twilight Privateer voyages. (If it isn't blocking or targeted by another spell or ability, it phases out.)
Whenever Twilight Privateer phases in, up to one other target creature voyages.

Resolute — Whenever Crackling Agama deals combat damage to a player, if Crackling Agama's power is greater than its base power, that player sacrifices an artifact or enchantment.

{W}, {T}: Target creature doesn't untap during its controller's next untap step.

Defender
When Ethereal Threshold enters, if it was cast, exile target artifact or creature. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Flash
When Hidden Sprout enters, put a +1/+1 counter on target creature.