msem-instigator

Exile up to three target cards from a single graveyard. You gain 3 life.

Whenever you cast your first noncreature spell each turn, you may draw a card. If you do, discard a card.

Whenever a creature you control becomes the target of a spell, that creature gets +3/+3 until end of turn.

Chamber of Splendor enters tapped.
When Chamber of Splendor enters, you may pay {1}. If you do, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
{T}: Add {C}.

Enchant creature
Enchanted creature gets -4/-0.
Mirage {U} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Enchant creature
Enchanted creature doesn't untap during its controller's untap step.
At the beginning of the upkeep of enchanted creature's controller, that player mills a card.

Whenever a creature enters under an opponent's control, you may have that player lose 1 life.
Unveil {2}{B}{R} ({2}{B}{R}: Transform this. Unveil only as a sorcery.)

This spell costs {1} less to cast if you have more life than an opponent and {1} less to cast if you control a Cleric.
Deathtouch

Target creature you control gets +1/+1 until end of turn. It deals damage equal to its power to target creature you don't control.

Flash
Flying
When Seeker Amalgam enters, you may counter target spell with mana value less than or equal to the number of Elementals you control.

Draw two cards. You may play an additional land this turn.
Coalesce {5}{G}{U} (You may cast this from your graveyard for {5}{G}{U}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

When Forlorn Farmhand dies, create a 1/1 colorless Spirit creature token.

Each creature you control with a +1/+1 counter on it has double strike.
If one or more +1/+1 counters would be put on a creature you control, put that many plus one +1/+1 counters on that creature instead.

Target creature gets -4/-0 until end of turn.
Crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)

Target player sacrifices a creature. Create a tapped 2/2 black Zombie creature token.

Archive 3 (As this enters, shuffle the top three cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever you draw a card from the archived library, target opponent loses 3 life unless they discard a card or sacrifice a nonland permanent.

When Yamisaran Guard enters, create a colorless Equipment artifact token with “Equipped creature gets +1/+1” and equip {1}.

Target creature gains indestructible until end of turn. Scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)
Fabled {3}{W} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

Whenever Infiltrator of the Anomalous deals combat damage to a player, add {R}. Until end of turn, you don't lose this mana as steps and phases end.

Soldiercycling {1}{W}, Wizardcycling {1}{U}, Zombiecycling {1}{B}, Warriorcycling {1}{R}, Elfcycling {1}{G} ({1}{G}, Discard this card: Search your library for an Elf card, reveal it, and put it into your hand, then shuffle.)
Sentinel of Latter Days is every creature type as long as it's in your library.

As an additional cost to cast this spell, sacrifice an artifact.
Draw three cards.

Enchant land
When Grace of Timber enters, put a +1/+1 counter on target creature you control.
Enchanted land has “{T}: Add two mana of different colors.”

When Ophidian Oracle enters, draw a card, then abound. (To abound, you may cast a spell that costs less than this from your hand without paying its mana cost.)
Recite {2}{G}{G} (You may cast this creature from your graveyard for its recite cost. If you do, exile it when it enters or if it would leave the battlefield.)

When Battlemage's Disruption enters, you may return target creature to its owner's hand.
{3}{U}, Sacrifice Battlemage's Disruption: Return target creature to its owner's hand.

Flying, trample
If a creature card would be put into an opponent's graveyard from anywhere, exile it with a soul counter on it instead.
Whenever Tamaak's Devourer deals combat damage to a player, put a creature card exiled with a soul counter on it onto the battlefield under your control.