msem-instigator

{T}: Add {C}.
{T}, Reappropriate: Add {G} or {U}. (Exile exactly two cards from your hand and/or graveyard.)

Put a +1/+1 counter on target creature.
Inscribe {2}{W} ({2}{W}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Whenever Memory of Fatalism dies or you cast a noncreature spell, each opponent loses 2 life and you gain 2 life.
{4}: Put Memory of Fatalism from your graveyard on top of your library.

Flying
Whenever you cast your second spell each turn, put a +1/+1 counter on Detached Specters.

Flying, first strike

When Traversing the Hellwastes enters, create a 1/1 green Scout creature token. It gains haste until end of turn.
Whenever a creature you control enters, you may pay 2 life. If you do, draw a card.

Return up to six target cards in your graveyard that don't share colors to your hand.
Exile Earthly Ambitions.

{U}, Exile an instant or sorcery card from your graveyard: Draw a card, then discard a card.
{R}, Exile an instant or sorcery card from your graveyard: Arcane Harvesters deals 1 damage to any target.

Destroy target creature or planeswalker. Draw a card.

Destroy target Human creature.

Enchant opponent
Creatures enchanted player controls get -1/-0.

Target player reveals their hand. Exile a nonland card from it and put a secret counter on it. As long as that card remains exiled, that player may pay {2} any time they could cast a sorcery to put it into their hand.
{X}{B}{B}, Exile Swipe Secrets from your graveyard: Until end of turn, you may cast target card you exiled with a secret counter on it and mana value X without paying its mana cost.

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
When Kantra of Old Majik enters, you may return target card from your graveyard to your hand.

Flying
When Imperator Namuzzar enters, search your library for an artifact or enchantment card, reveal it, put it into your hand, then shuffle.
Civilized — Lammasu you control get +2/+2 and have hexproof as long as you control an artifact, a creature, and an enchantment.

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Whenever Passionate Painter becomes untapped, you may discard a card. If you do, draw a card, then transform Passionate Painter.

Rhapsody {3}{R}{R} (Pay {3}{R}{R} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
Whenever Vindictive Guardian or another creature you control enters, if that creature's power is 4 or greater, create a Treasure token.

When Dreamsight Well enters, shuffle any number of cards you own from outside the game into your library.
Whenever you cast a creature spell, if you have more cards in your library than each opponent, draw a card.

When Sunwright Scion enters, put a +1/+1 counter on each other creature you control.
At the beginning of each combat, you may have target creature with a +1/+1 counter on it gain your choice of vigilance, lifelink, or trample until end of turn.

Create a 2/2 white Angel creature token with flying.
Coalesce {6}{W}{W} (You may cast this from your graveyard for {6}{W}{W}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Flying

Concord — You may cast this spell as though it had flash if there are four or more card types among permanents you control.
When Krill-Clan Guardian enters, it fights up to one other target creature. If that creature would die this turn, return it to its owner's hand instead.

Defender
Whenever another player casts an instant or sorcery spell, Devouring Spellroot gets +2/+2 until end of turn.

When Escaped Ooze enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
{3}{G}: Put a +1/+1 counter on Escaped Ooze.

Enchant creature
Enchanted creature can't attack or block, and its activated abilities can't be activated.

When Bellani Mystic enters, target player mills two cards.