msem-instigator

Transformed creatures you control get +2/+2.

When Student of the Scroll enters, scry 2.

Whenever a creature card is put into your graveyard from the battlefield, exile it. You lose life equal to that card's mana value. Put it onto the battlefield tapped at the beginning of your next upkeep.

Menace
Ferocious — Whenever Merciless Xun Huang attacks, if you control a creature with power 4 or greater, defending player sacrifices a permanent.

Menagerie — When Lurking Feralynx enters, if there are five or more creature types among creatures you control, you may search your library for a card named Lurking Feralynx, reveal it, put it into your hand, then shuffle.

Legacy (You may play this side of this card only from your graveyard. Exile it if it would leave the battlefield or not resolve.)
Whenever you attack, you may discard up to X cards, where X is the number of attacking creatures you control. Draw a card for each card discarded this way.

Enchant creature
Enchanted creature gets +3/+1 and has haste.

Flying
Augmented — Whenever you cast a spell, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on Enlightened Guardian. It loses this ability and gains “Whenever this creature attacks, draw two cards.”

{T}: Add {R} or {W}. You lose 1 life unless you have less life than an opponent.

Flying
When Illuminating Archangel enters, target creature gets +X/+X and gains vigilance and first strike until end of turn, where X is the number of permanents you control that are Angels, Demons, Faeries, and/or Spirits.

{T}: Draw a card, then discard a card.
Whenever you cast an instant or sorcery spell, untap Exchange Scholar.

Bristling Skoki has first strike as long as it's attacking.
Whenever Bristling Skoki blocks a creature, you may have it deal damage equal to its toughness to that creature.

Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Enchant land
When Pilgrim's Vantage enters, you may put a +1/+1 counter on target creature.
Enchanted land has “{T}: Add two mana of different colors.”

Whenever you cast a noncreature spell, you may pay {U}. If you do or the spell was cast from your graveyard, draw a card.

Put target artifact, enchantment, or card in a graveyard on the bottom of its owner's library.

Koth's Retaliation deals 4 damage to target creature. When that creature dies this turn, exile its controller's graveyard.

Trample, haste
When Relonche Cavalry enters, other creatures you control get +1/+0 and gain trample and haste until end of turn.

Flash
Enchant player
When Curse of Doubt enters, counter target spell enchanted player controls unless they pay {2}.
{4}{U}: Enchanted player mills three cards.

Return target nonland permanent to its owner's hand. Then you may pay {U}{U}. If you do, copy Resonating Force and you may choose new targets for the copy.

Advance {2}{R} (Cast this for {2}{R} to advance it as it enters. {2}{R}: Advance this as a sorcery.)
Haste
Whenever Soulblade Warrior advances, it gets +2/+0 until end of turn.

Barren Boneyard enters tapped.
{T}: Add {B}.
{2/B}{2/B}: Barren Boneyard becomes a 2/3 black Elemental creature with deathtouch until end of turn. It's still a land.

Prowess
Whenever Knight-Academic attacks, scry 1.

When Living Hoard enters, create a Treasure token.
{R}, Sacrifice an artifact: Living Hoard gets +2/+0 until end of turn.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Concord — Once each turn, when an opponent casts a spell or activates an ability that targets a Merfolk or enchantment you control, you may counter that spell or ability if there are four or more card types among permanents you control.