msem-instigator

{B}, {T}: Exile target creature card from a graveyard. You gain 2 life.
{1}{B}, {T}: Mill three cards. You lose 2 life.
{3}{B}{B}, {T}, Sacrifice Ethics and Reanimation: Return target creature card from your graveyard to the battlefield. Activate only as a sorcery.

When Elvish Skyranger enters, search your library for a card with a basic land type, put it onto the battlefield tapped, then shuffle.

Neon Claw Assassin gets +1/+0 and has first strike as long as you've discarded a card this turn.

Whenever a player casts an instant or sorcery spell from their hand, you may exile that card as it resolves instead of putting it anywhere else.
Whenever Skill Sketcher attacks, you may cast a card exiled with it. That spell costs {X} less to cast, where X is Skill Sketcher's power.

{1}{B}, Sacrifice another creature: Draw a card and create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)
{2}{B}, Sacrifice three Idols: Return Demon of Hubris from your graveyard to the battlefield. Activate only as a sorcery.

Other creatures you control get +2/+2.

Target creature gets -4/-4 until end of turn. If that creature would die this turn, exile it instead.
Cycling {2} ({2}, Discard this card: Draw a card.)

{4}{R}: Blind Tunneler gets +3/+0 until end of turn.

{T}: Add {C}. Spend this mana only to cast a creature spell with a creature type no creature you control has.

Choose one —
• Radiant Outburst deals 3 damage to target creature.
• Harmonize twice. (To harmonize, trigger up to one harmony of a permanent you control.)

Enchant creature
Enchanted creature gets +2/+1 and is a black Zombie in addition to its other colors and types.

At the beginning of your end step, if you control two or more tapped creatures, you may exile target creature. If you do, return that card to the battlefield under its owner's control.

Tap up to two target creatures an opponent controls. Those creatures don't untap during their controller's next untap step.
Create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

As The Mistake enters, choose a card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.
Unveil {5} ({5}: Transform this. Unveil only as a sorcery.)

If you control ten or more nonland permanents, you get an emblem with “At the beginning of your end step, return target permanent card from your graveyard to the battlefield.”
Destroy all nonland permanents.

Menace
Disgraced 1 (This enters with a -1/-1 counter. Whenever it deals combat damage to a player, remove all -1/-1 counters from it.)

When Crystalline Golem enters, choose a color. You gain 1 life for each permanent of that color you control.

Draw a card.
Showcase {3}{U} (Then if you cast this for its showcase cost, create a 1/1 red Bard creature token that can't block and exile this. Whenever it attacks, you may cast a free copy of this.)

Livia's name is Senaturian Legion in addition to its other names as long as it's on the battlefield.
At the beginning of your upkeep, conjure a card named Senaturian Legion into your hand, then discard a card. (It's a 1/1 Human Soldier for {W}{W} that gets +1/+1 for each other creature on the battlefield named Senaturian Legion.)
Other Soldiers you control have haste.

Blessed Barrage deals 5 damage divided as you choose among any number of attacking or blocking creatures.

Whenever you cast an enchantment, instant, or sorcery spell, create a 1/1 blue Jellyfish enchantment creature token with slipstream. (It can't be blocked as long as only creatures with slipstream are attacking.)

When Red Flower Assassin enters, destroy target creature.
Revive {5}{B} ({5}{B}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

When this creature enters, if you gained or lost life this turn, it seeks valor. (Give it that Oath Aura. Fulfill it by it dealing combat damage to a player to create a 2/1 white Soldier token.)

Tap up to two target creatures. Those creatures don't untap during their controllers' next untap steps. Scry 1.

You may tap or untap target nonland permanent.
Catalyze. (The next spell you cast this turn costs {1} less to cast.)