msem-instigator

Draw a card, then each player draws a card.

Enchant creature
Enchanted creature gets +3/+3 and has flying.

Flash
When Devious Naiad enters, exchange control of it and target creature until end of turn. Untap that creature. It gains haste until end of turn.

Equipped creature gets +0/+3.
Whenever equipped creature dies, draw a card.
Equip {3}

Until end of turn, target creature gets +2/+2, then an additional +2/+2 for each card and token merged with it.

{1}{B}, Mill three cards: Return Dredging Aberration from your graveyard to your hand.

{U}, Exile an instant or sorcery card from your graveyard: Draw a card, then discard a card.
{R}, Exile an instant or sorcery card from your graveyard: Arcane Harvesters deals 1 damage to any target.

When Occult Mastermind enters, create two 2/2 black Zombie creature tokens. When Occult Mastermind is no longer on the battlefield, sacrifice two Zombies.

[+2]: Create a Vial token. (It's an artifact with “1, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
[–3]: Sacrifice another nonland permanent. If you do, destroy target nonland permanent.
[–9]: You get an emblem with “At the beginning of your end step, create Fallen One, a legendary 6/6 black Faerie Angel Avatar creature token with flying.”

When Divine Shell enters, create three Function tokens with “Tap target creature.” (They're enchantments. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Fulfill the Contract deals X damage to target creature or planeswalker and you gain X life, where X is the number of Satrapies you control.
Satrapycycling {2} ({2}, Discard this card: Search your library for a Satrapy card, reveal it, put it into your hand, then shuffle.)

Choose one —
• Exile target artifact.
• Exile target creature with flying.
• Exile target card in a graveyard.

When Faithless Deserter enters, you may sacrifice a creature. If you do, each opponent sacrifices a creature.

{U}{R}{W}, Discard a card named Sha'Iv, God of Order: Sha'Iv gains indestructible and becomes a God creature in addition to its other types.
Whenever Sha'Iv enters or attacks, choose target creature an opponent controls. Untap it, then tap each other creature that player controls. They don't untap during their controller's next untap step.

Search your library for three land cards with different names, reveal them, then shuffle. Put one of those cards onto the battlefield, one into your hand, and one into your graveyard.

Creatures can't attack you or a planeswalker you control unless their controller pays {2} for each of those creatures.
Creatures can't block Ghastly Scraper unless their controller pays {2} for each of those creatures.

Manifest all cards from all players' hands. (To manifest a card, put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

Once each turn for each card type, when you cast a spell with that type, you may copy it. You may choose new targets for the copy. If it's a permanent spell, the copy gains haste and “At the beginning of the end step, sacrifice this permanent.”
Whenever a permanent you control dies, it deals 1 damage to each opponent.

Create three 1/1 green Saproling creature tokens.

Put target creature on top of its owner's library.
Quickdraw {2}{U} (When a creature you control blocks or becomes blocked, you may cast this spell for {2}{U}.)

When Rice Cultivator enters, search your library for a basic Plains card or an artifact card with a mana ability, reveal it, put it into your hand, then shuffle.

When Masha's Lightbound becomes tapped for the first time each turn, untap Masha's Lightbound and each other creature you control.
{W}, {T}: Exile target card from a graveyard.

Whenever Baljurn, the Runelord or another nontoken artifact or enchantment you control enters, create a 0/0 blue Construct artifact creature token. Put a +1/+1 counter on each artifact and/or enchantment creature you control other than Baljurn.

Exile target card from a graveyard. Create a 1/1 black Worm creature token.
Fuse (You may cast one or both halves of this card from your hand.)

When North Ward Settler enters, choose one —
• Create a 1/1 white Dwarf creature token.
• Put a +1/+1 counter on North Ward Settler.