msem-instigator

Choose target creature, then flip a coin. If you win the flip, Long Shot deals 5 damage to that creature. Otherwise, return Long Shot to its owner's hand.

At the beginning of your upkeep, you may choose a color, then exile two cards of that color from your graveyard. If you do, return a creature, instant, or sorcery card of that color from your graveyard to your hand.

Flash (You may cast this spell any time you could cast an instant.)
When Replicator Mage enters, you may create a token that's a copy of target creature that's attacking you. Exile that token at end of combat.

{T}: Add {G}. When that mana is used to cast a spell with mana value 5 or greater, you may untap Performer of Growth and transform it.

When this artifact enters, create a 2/1 white Soldier creature token. 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.)
Whenever an enchantment you control enters, draw a card.

If a creature an opponent controls would die, exile it instead.
Whenever Rocket Poacher deals combat damage to a player, put a card exiled with it onto the battlefield under your control.

Enchant creature
Enchanted creature gets +2/+2 and has “Whenever this creature attacks, tap target creature defending player controls.”

Codex — Ser Wayver, the Broken Hour; Suzume Oshiruko; Aguri, Shadow of Doubt; Sukhar, Consort to the Dark; Chi Lee of the Underworld. (As this enters, conjure its contents into a shuffled face-up additional library.)
You may spend mana as though it were mana of any color to cast this codex's contents.

Draw three cards, then discard two cards.

Haste
Battalion — Whenever Fellor Tactician and at least two other creatures attack, creatures you control get +1/+1 until end of turn.

Reach
{4}{B}: Each opponent loses 2 life and you gain 2 life.

Target opponent reveals their hand. You choose a nonland card from it. That player discards that card.
Create a Function token with “Draw a card if a player discarded a card this turn.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Renown 2 (When this creature deals combat damage to a player, if it isn't renowned, put two +1/+1 counters on it and it becomes renowned.)
When Gilded Champion becomes renowned, you may search your library for an Equipment or Aura card, reveal it, put it into your hand, then shuffle.

Solar Flare deals 3 damage to any target. You gain 3 life.

Exile target creature. Return that card to its owner's hand at the beginning of its owner's next end step.

When Everything Is Going Great enters, create a 4/4 Elemental creature token that's all colors.
At the beginning of your end step, exile up to one other target nonland permanent you control, then return it to the battlefield under your control.

Tithe (When this creature enters, you may tap three other artifacts and/or creatures you control.)
When Cataclysmic Preacher's tithe is paid, return target instant or sorcery card from your graveyard to your hand.

Flying
Legendary spells you cast cost {1} less to cast.
{W}{U}{B}{R}{G}: Search your library or graveyard for a legendary card, reveal that card, and put it into your hand. If you searched your library this way, shuffle.

Whenever you cast an instant or sorcery spell, put a +1/+1 counter on Kederekt Seawitch, then scry 1.

Vampire Partaker can't block.
Sacrifice a creature: Put a +1/+1 counter on Vampire Partaker. You gain 1 life. Activate only as a sorcery.

Festive Servitor gets +1/+1 for each color among spells you've cast this turn.
{2}: Add one mana of any color.

Vanishing 4 (This permanent enters with four time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When Doomed Fate leaves the battlefield, if it had no time counters on it, destroy all nonland permanents.

When Street Stalker enters, target opponent loses 1 life for each creature you control named Street Stalker.

At the beginning of your upkeep, you may search your library for a permanent card with mana value 1 or less, put it onto the battlefield, then shuffle.

Menace
Inspired — Whenever Soul Engulfer becomes untapped, each opponent loses 4 life.