msem-instigator

{T}: Draw a card. Activate only if Theoretical Scholar is embattled. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Trial 3 (As you cast this spell, an opponent of your choice may pay 3 life. If they don't, they fail the trial.)
Target creature gets -1/-1 until end of turn. If that creature's controller failed the trial, it gets -4/-4 until end of turn instead.

Flying
When Angel of Despair enters, destroy target permanent.

When Grim Festivities enters or at beginning of your upkeep, you may return a creature card from your graveyard to the battlefield under your control. If you do, each opponent may return a creature card from their graveyard to their hand.

Create a 1/1 white Soldier creature token. Then put a +1/+1 counter on a creature you control.

Creature tokens you control get +1/+1 and have distorted. (They can be blocked by tapped creatures but not untapped creatures.)

Trample
Seasoned Adventurer enters with two +1/+1 counters if you control seven or more lands.

Choose a Function added to Rapid Recursion. Create a Function token with those effects. (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)
Draw a card.

Search your library for a creature or planeswalker card, reveal it, put it into your hand, then shuffle.

When Journey through Uwaito enters, draw a card, then choose a creature card name.
Whenever a creature you control with the chosen name dies, each opponent discards a card.

Choose one —
• Target creature gets +1/+0 and gains indestructible until end of turn.
• Tap target creature. Put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
• Scry 1, then draw a card.

When Sacrifice to Setar dies, surveil X, where X is the amount of damage dealt to them this turn. Draw a card. Then if X is 3 or greater, you may return Sacrifice to Setar to the battlefield transformed.

Whenever one or more creatures you control with counters on them attack, draw a card.

Eerie Wildwood enters tapped. When it enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
{T}: Add {R} or {G}.

Menace (This creature can't be blocked except by two or more creatures.)
Cycling {R} ({R}, Discard this card: Draw a card.)

{T}: Add {C}.
Ascend—Tap ten untapped permanents you control. (Tap ten untapped permanents you control: Exile this land, then return it to the battlefield transformed. Ascend only as a sorcery.)

Whenever Voracious Spawn enters or attacks, exile up to one target card from a graveyard. If you exile a permanent card, put a +1/+1 counter on Voracious Spawn. If you exile a nonpermanent card, you gain 1 life.

Prismatic — Whenever you cast a multicolored spell, you may discard a card. If you do, draw a card.

Flash
Rhapsody {5}{U}{U} (Pay {5}{U}{U} to cast this as a 4/4, or once it is in play to make it become a 4/4.)
Animus Channeler's rhapsody cost can be paid any time you could cast an instant.

Guide to the Wayward enters with a +1/+1 counter on it.
{1}{W/U}, {T}: Permutate. (You may remove a counter from a creature you control. If you do, put two +1/+1 counters on a different creature you control.)

Put X -1/-1 counters on up to one target creature. Exile up to one target card from a graveyard.

Target creature gains double strike until end of turn.
Showcase {2}{R}{R} (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.)

Enchant creature
When Paid in Blood enters, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
Enchanted creature gets +1/+1 and has lifelink.

Inviolable Realms enters tapped unless you control two or more other lands.
{T}: Add {U}.
{T}, Pay 1 life: Add {W} or {B}.

Whenever a Project you control enters, create two 1/1 colorless Construct artifact creature tokens.
Whenever a creature leaves the battlefield, you may put a progress counter on a Project you control.