msem-instigator

{T}: Add {C}.
{3}, {T}, Sacrifice Abandoned Sanctuary: Search your library for a land card with a basic land type and put it onto the battlefield tapped, then shuffle.

Embellish {4}{W} (If you cast this spell for {4}{W}, create a 1/1 blue Thopter artifact creature token with flying when it enters.)
When Meticulous Mechanist enters, scry 1.

Creatures you control get +2/+0 until end of turn. Each creature you control with a +1/+1 counter on it gains menace until end of turn.

Flying
Whenever Hao'Tai deals combat damage to a player, that player exiles the top five cards of their library and separates them into two piles. Put an ember counter on each card in the pile of your choice. You may play cards from exile with ember counters for as long as they remain exiled.

{T}: Add one mana of any color.
Augmented — Whenever a nontoken creature you control enters, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on it.

Flash
When Veilborn Meddler enters, counter target spell if its mana value is less than or equal to Veilborn Meddler's power.
Whenever you cast a spell during an opponent's turn, put a +1/+1 counter on Veilborn Meddler.

Double strike
Attain {3}{R} ({3}{R}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

Flying
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.)

Friend of the Woods has hexproof as long as it has a +1/+1 counter on it.
{1}{G}, {T}: Put a +1/+1 counter on Friend of the Woods.

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.

When Faceless Animist dies, you may return another target colorless card from your graveyard to your hand.

Menace
As long as you control exactly one other creature, that creature gets +1/+1 and has menace.

First strike
Whenever Guardian of the Eclipse attacks, you may exile another target attacking creature you control, then return it to the battlefield under your control tapped and attacking.

At the beginning of your upkeep, if you don't control any Imps, you may pay {B}. If you do, create a 1/1 black Imp creature token.
Sacrifice a creature: Each opponent loses 1 life.

When Fel Alston, Halfway Queen enters, return target creature card from your graveyard to the battlefield. Then exile that creature unless Fel Alston was cast for its escape cost.
Escape—{1}{W}{U}{B}, Sacrifice two creatures. (You may cast this card from your graveyard for its escape cost.)

Instant and sorcery spells you control have leitmotif. (Exile that spell as it resolves if you cast it from your hand. When you next cast a spell that shares a color with that card, you may cast it from exile 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.)
You may have Witch of Shifting Waters enter as a copy of any creature on the battlefield, except it's an enchantment in addition to its other types.

Enchant creature
As long as you control an untapped creature, enchanted creature can't attack or block.

Catalina's Turf enters tapped.
When Catalina's Turf enters, you may mill two cards.
{T}: Add {B} or {R}.

As an additional cost to cast this spell, sacrifice a creature.
Put X +1/+1 counters on target creature you control, where X is the sacrificed creature's power. You gain X life.

Deathtouch
Whenever Operative SCARY attacks or you cast a green or white spell, you may draw a card. If you do, you lose 2 life.

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)
Lifelink
When Leyran-Pack Outcast attacks, if it's alpha, each player sacrifices a creature.

When Vespercloak Vampire dies, create a 1/1 black Bat creature token with flying and lifelink.
Foreshadow {3}{B} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

Creature spells you cast cost {1} less to cast.
Whenever you attack, target attacking creature you control gets +1/+1 until end of turn. If it's legendary, put a +1/+1 counter on it instead.