msem-instigator

Whenever you cast a noncreature spell, put a quest counter on Gate to the Beyond.
At the beginning of your upkeep, if there are three or more quest counters on Gate to the Beyond, you draw a card and you lose 1 life. Then if there are six or more quest counters on it, each opponent loses 2 life.

Choose one or both —
• Riverboat Assault deals 3 damage to target creature.
• Target creature gets +3/+3 until end of turn.

Whenever a creature dealt damage by Slave Child this turn dies, you may pay {B}. If you do, transform Slave Child.

Motivate 2 (When this creature enters, you may motivate target creature with less power than this by putting two +1/+1 counters on it.)
Whenever a creature you control becomes motivated, you gain 2 life.

Equipped creature gets +3/+1 and has reach.
Equip {4}

{T}, Pay 1 life: Add {R} or {W}.
{1}, {T}, Sacrifice Backstage Rooms: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

First strike
Angel spells you cast cost {2} less to cast.
As long as you control an Angel, prevent all noncombat damage that would be dealt to Traft, Lunarch's Edge.

Search your library for a card, put that card into your hand, then shuffle.
Whenever you cast a spell with mana value 5 or greater, you may cast Words of Eternity from your graveyard without paying its mana cost. If you do, exile it instead of putting it into your graveyard as it resolves.

Search your library for a cryptic card, reveal it, put it into your hand, then shuffle. (Artifacts, enchantments, and modal spells are cryptic.)

Equipped creature gets +2/+2.
Whenever equipped creature attacks, the next time an instant or sorcery source you control would deal damage to a creature, player, or planeswalker this turn, it deals that much damage plus 2 instead.
Equip {2}

Flying
Whenever an embattled creature you control attacks, tap target creature defending player controls. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Voracious 2 (As this enters, you may sacrifice up to two artifacts and/or creatures. This creature enters with that many +1/+1 counters on it.)
When Territorial Bear dies, you may return up to two target artifact cards from your graveyard to your hand.

Fortress Arena enters tapped.
{T}: Add {R} or {W}.
{2}{R}{W}, {T}, Sacrifice Fortress Arena: Draw a card.

Create four 1/1 white Soldier creature tokens, then put a +1/+1 counter on each of up to four creatures you control. Draw a card for each creature you control with power 4 or greater. You gain 4 life.

Flash
When Threadripper Savant enters, put a stun counter on up to one target creature.

Enchant creature
Enchanted creature gets +1/+2.
Whenever enchanted creature attacks, scry 1.

Enchant player
At the beginning of enchanted player's upkeep, if they control two or more creatures and/or planeswalkers, they sacrifice a creature or planeswalker.

At the beginning of your upkeep, mill a card.
{1}, Exile three cards from your graveyard: Put a -1/-1 counter on target creature.

When Thallid Cultivator dies, mill four cards. Return a creature card milled this way to your hand.

Menace
Whenever one or more cards leave your graveyard or Watchers of the Veil leaves your graveyard, you may draw a card. If you do, discard a card.

Indestructible
As long as your devotion to black and red is less than seven, Mogis isn't a creature.
At the beginning of your upkeep, each player discards a card. Then you draw a card. If an opponent can't discard a card or discarded a land card, you create a 2/3 red Minotaur creature token.

[+1]: Return up to one target Aura card from a graveyard or on the battlefield to its owner's hand.
[–2]: Sacrifice an enchantment. If you do, return target enchantment card from your graveyard to the battlefield.
[–6]: Draw three cards. Until end of turn, you may cast enchantment spells without paying their mana costs.

When Helicos-Drowned Captain enters, create a black Aura Curse enchantment token named Marked for Death attached to target player. The token has enchant player and “At the beginning of enchanted player's upkeep, that player loses 1 life.”

Attacking creatures get -X/-0 until end of turn.