msem-instigator

Counter target creature spell or target spell that targets a creature an opponent controls.

Artifact creatures you control get +1/+1.
{1}{U}, Discard an artifact card: Search your library for an artifact card, reveal it, put it into your hand, then shuffle.

Once during each of your turns, when you cast an instant or sorcery spell, you may create a Function token with that spell's 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. A spell's effects includes added functions.)

As an additional cost to cast this spell, return a creature you control to its owner's hand or pay {2}.
Counter target spell.

When Jeffery Stages the Finale enters, search your library for a legendary blue card, reveal it, put it into your hand, then shuffle.
Whenever you cast a spell with mana value 5 or greater, return up to one target nonland permanent to its owner's hand.

When Journey through Odaya enters, draw a card, then choose a creature card name.
Creatures you control with the chosen name can't be blocked.

When Journey to the Syzygy Spire enters, draw a card, then choose a creature card name.
Whenever a creature you control with the chosen name deals combat damage to a player, draw a card.

(Choose only one work as a sorcery to add its ability.)
When Juyu Offering Pool enters, reveal the top five cards of your library. You may put a noncreature card from among them into your hand. Put the rest on the bottom of your library in any order.
{1}{U}: Scales of Shara
Whenever you cast a noncreature spell, put a +1/+1 counter on target creature you control.
{6}{U}{U}: Eye of Shojiro
Whenever you cast a noncreature spell, create an 8/8 blue Kraken creature token.

Siphon (Each -1/-1 counter you put on your creatures up to their remaining toughness while casting this pays for {1}.)
Draw three cards.

Target creature gets -4/-0 until end of turn.
Flashback {U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Paranoia {2}{U} (You may cast this spell for its paranoia cost when a permanent you control leaves the battlefield.)
Put target artifact or creature on top of its owner's library.

Reverberate {2}{U} (When you cast this spell, copy it if you paid its reverberate cost. You may choose new targets for the copy.)
Target creature gets +0/+3 and gains hexproof until end of turn.

Fleeting {2}{U} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)
[+1]: Any number of other target nonland permanents lose all abilities until your next turn.
[0]: You may tap an untapped creature you control. If you do, draw two cards.
[–2]: Create a token that's a copy of target creature, except it loses all abilities until end of turn.

When Lammasu Roost enters, create a 2/2 blue Lammasu creature token with flying.
{3}{U}: Scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Forebode three times, then untap each Omen you control. Until end of turn, if you would draw a card while your library has no cards in it, you win the game instead. (Create three tapped colorless Omen artifact tokens with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)

Counter target spell unless its controller pays {4}. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Repeat the following process X times. Exile a creature you control, then return it to the battlefield under your control.
Exile Lazaire's Conjuring.

Whenever target creature deals combat damage to a player this turn, draw two cards.
Fuse (You may cast one or both halves of this card from your hand.)

Counter target instant or sorcery spell you don't control unless its controller copies it twice. You gain control of those copies and may choose new targets for them.

As an additional cost to cast this spell, exile a card from your graveyard.
Counter target spell with mana value less than or equal to the exiled card's mana value.

Enchant creature
As Legacy of Highpoint enters, choose a creature type.
Enchanted creature gets +2/+2, has flying, and is the chosen type in addition to its other types.

At the beginning of your end step, draw a card, then discard a card.
Whenever you cast a spell with mana value 5 or greater, if it's an instant or has flash, you may counter target spell.

This spell costs {2} less to cast if you've cast another spell this turn.
Draw two cards, then put a card from your hand on top of your library.

Untap up to two target lands you control. Those lands become the basic land type of your choice until end of turn.
Draw a card.

Enchant creature
Enchanted creature has flying.
Whenever enchanted creature deals combat damage to a creature, you may untap enchanted creature.