msem-instigator

Menace
Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{3}{R}: Another target creature you control gains menace until end of turn.

Trample
Whenever you cast a noncreature spell, crystallize. If you create a Treasure this way, Heartforge Savant deals 1 damage to you for each Treasure you've created this turn. (Put a +1/+1 counter on a creature you control or create a Treasure.)

Wither (This deals damage to creatures in the form of -1/-1 counters.)
{X}{R}: Hearth Dweller gets +X/+0 until end of turn.

Target permanent you control gains hexproof until end of turn. If that permanent is a creature, it also gets +1/+1 until end of turn.

Flying, vigilance, deathtouch, lifelink

If one or more counters would be put on a creature you control, that many plus one of each of those kinds of counters are put on that permanent instead.

Flying
When Heartless Host enters, arm target creature. (Create a colorless Equipment artifact token with “Equipped creature gets +1/+0” and equip {2}, then attach it to that creature.)

Bloodprice {U} (You may cast this card by sacrificing a creature and paying its bloodprice.)
Counter target spell unless its controller pays {4}.

At the beginning of your upkeep, if you have less life than an opponent, you lose 1 life and you draw a card.

Menace
Sacrifice a Goblin: Heartless Warleader gets +2/+2 until end of turn.

Deathtouch
Whenever another creature dies, its controller discards a card at random.

Augmented — Whenever you cast a spell from your hand, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, exile cards from the top of your library until you reveal a nonland card with mana value less than that spell's mana value. You may cast that card without paying its mana cost. Put the revealed cards not cast this way on the bottom of your library in a random order.

Kicker {2}{B} (You may pay an additional {2}{B} as you cast this spell.)
Flying
When Heartstabber Mosquito enters, if it was kicked, destroy target creature.

Enchant creature
When Heartstrings leaves the battlefield, exile enchanted creature.
Whenever enchanted creature attacks or blocks, exile it at end of combat.

Creature spells you cast cost {1} less to cast.

Whenever you attack, you may pay {R}{W}. If you do, create a tapped and attacking token that's a copy of target attacking creature. Sacrifice the token at the beginning of the next end step.

Reach

Whenever you scry, you gain 1 life for each card you looked at while scrying this way.

Haste
Crew 1 (Tap any number of creatures you control with total power 1 or greater: This Ship Vehicle becomes an artifact creature until end of turn.)

Put a +1/+1 counter on up to one target creature. Untap it. You gain 3 life.

Heat Blast deals X damage to target creature or planeswalker.

Heat Ray deals X damage to target creature.

Whenever a creature blocks, Heat of Battle deals 1 damage to that creature's controller.

Enchant creature
Prevent all damage that would be dealt by enchanted creature.
{R}, Sacrifice Heat of Day: It deals 2 damage to enchanted creature.

Until end of turn, gain control of target creature and it gains haste and shimmer. Untap it. (Whenever it attacks this turn, create a tapped and attacking token that's a copy of it. Exile that token at the beginning of the end step.)