msem-instigator

Haste (This creature can attack and {T} as soon as it comes under your control.)
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Whenever Vindictive Pyromancer perseveres, it deals 1 damage to any other target. (A creature perseveres when it survives damage.)

Dead Man's Hand enters tapped.
{T}, Sacrifice Dead Man's Hand, two permanents with mana value 1, and two permanents with mana value 8: Target player loses the game.

Flying
Whenever Circumspect Flock perseveres, create a 1/1 white Bird creature token with flying. (A creature perseveres when it survives damage.)

Create a 1/1 blue Illusion creature token with “This gets +1/+1 for each other Illusion you control.”
Acquiesce (If you cast this spell from your hand, exile it as it resolves. When one or more creatures you control deal combat damage to an opponent, you may cast this card from exile without paying its mana cost.)

Flying
When Obsidian Hellkite dies, it deals 2 damage to up to one target creature or planeswalker. If that creature or planeswalker would die this turn, exile it instead.
Foreshadow {4}{R}{R} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

Look at target opponent's hand. You may exile a noncreature, nonland card from it. For as long as that card remains exiled, its owner may cast it. A spell cast this way costs {2} more to cast.
Draw a card.

Enchant creature
Enchanted creature gets -3/-0.
Spells that target enchanted creature cost {1} more to cast.

Marinton Occultist can't block or be blocked.
Whenever one or more cards are put into a player's graveyard from their library, Marinton Occultist gets +1/+1 until end of turn.

Lifelink
When Black Curtain Enforcer enters, you may return target creature card with mana value 3 or less from your graveyard to your hand.

Draw two cards, then discard two cards. Then if you cast Price of Wisdom from your graveyard, create a 3/3 blue Sphinx creature token with flying.
Flashback {4}{U}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

When Bal's Descent enters, each player sacrifices a creature, discards two cards, and mills three cards.
{1}{B}{B}: Transform Bal's Descent. Activate only if your fealty to Swamps is five or greater.

You may activate equip abilities any time you could cast an instant if you pay an additional {1} to activate them.
Armed — Equipped creatures you control get +1/+1 as long as Master of Steel is equipped.

{T}: Kanaan Wardriver deals 1 damage to target creature you control. That creature gains haste until end of turn.

Menace
At the beginning of your end step, if Vartrossen Vandals didn't attack this turn, transform it.

Flying
Aedryd, Spectral Liege's power and toughness are each equal to the number of creatures you control.
{2}{W/U}: Another target creature you control gains flying until end of turn. When that creature leaves the battlefield this turn, create a 1/1 white Spirit creature token with flying.

Menace
Whenever an opponent activates an ability that isn't a mana ability, Flensing Tormentor deals 1 damage to that player.

Flying
{3}{W}, {T}: Exile another target creature you control, then return that card to the battlefield under your control.

Enchant creature
When Make Way enters, draw a card.
Enchanted creature can't block.

When Exiled Necromancer enters, return target permanent card with mana value 1 or less from your graveyard to the battlefield.

Investigate ten times. (Create ten colorless Clue artifact tokens with “{2}, Sacrifice this artifact: Draw a card.”)

When Geistmage's Grimoire enters, draw two cards.
{4}{U}, {T}: Target creature can't be blocked this turn.

This spell costs {X} less to cast, where X is the number of Dwarves and Elves you control.
Trample, haste
Whenever Harl and Finn attacks, other creatures you control get +1/+1 and gain trample until end of turn.

If a source would deal damage to you or a permanent you control this turn, prevent all but 1 of that damage.
Metamorph {1}{W} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up and cast it at any time for its metamorph cost.)