msem-instigator

Create a token that's a copy of target nonland permanent you control with mana value X.
Flashback—{U}{U}, Exile cards from your graveyard with exactly X card types among them. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Counter target creature spell. You may cast a copy of that spell. (You still pay its costs. The copy becomes a token.)

Reprise {4}{U} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)
Target player mills a card. Create X tapped 2/2 black Zombie Pirate creature tokens, where X is the total number of cards milled by this spell.

Copy target instant or sorcery spell. You may choose new targets for the copy.

Each player can't cast more than one spell each turn.
You may cast spells from your hand without paying their mana costs.

{U}, Put a travel counter on Endless Discoveries: Draw a card. This ability costs {1} more to activate for each travel counter on Endless Discoveries.
{3}{U}{U}, Sacrifice Endless Discoveries: Return target instant or sorcery card with mana value less than or equal to the number of travel counters on Endless Discoveries from your graveyard to your hand.

Whenever you cast a noncreature spell, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)

Draw a card for each creature you control.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

Any number of target players mill twice X cards, where X is the number of artifacts and enchantments you control. Then you may cast a nonland card with mana value X or less from a graveyard without paying its mana cost. You can't cast more spells this turn.

{U}: Enduring Rockshell gets -1/+1 until end of turn.
Whenever Enduring Rockshell perseveres, draw a card, then discard a card. (A creature perseveres when it survives damage.)

{U}: If Engrossed Reader doesn't have flying, put a flying counter on it.
{1}{U}: If Engrossed Reader has flying, draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on Engrossed Reader.
{1}{U}{U}: If Engrossed Reader has a +1/+1 counter on it, it becomes a copy of another target creature until end of turn.

Whenever a creature attacks you or a planeswalker you control, upgrade Enigmatic Protector. (Give it one of the listed counters it doesn't already have.)
• +1/+1
• Flying
• Prowess

Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Scry 1.
[Lore III] Target creature you control can't be blocked until end of turn.

Flying
Augmented — Whenever you cast a spell, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on Enlightened Guardian. It loses this ability and gains “Whenever this creature attacks, draw two cards.”

Flash
When Enlightened Lizard enters, counter target noncreature spell.

Enchant creature
Enchanted creature loses all abilities and is a blue Wizard creature with base power and toughness 1/1.

Whenever Ensouled Thief attacks, upgrade it. (Give it one of the listed counters it doesn't already have.)
• +1/+1
• Prowess

{1}: Target Equipment becomes a colorless 3/3 Construct artifact creature until end of turn. (Equipment that's a creature can't equip a creature.)
{2}{U}{U}, {T}: Return target artifact card from your graveyard to your hand.

Flying
Whenever Entali Aeromancer attacks, Elementals you control gain flying until end of turn.

Each player shuffles their hand and graveyard into their library. Then each player draws seven cards. If you didn't control a blue legendary creature or planeswalker as you cast this spell, discard three cards. Exile Entelan Erasure.

When Entelan Savant enters, scry 2.

Return any number of target nonland permanents with different mana values to their owners' hands. If seven or more permanents were returned this way, you may cast spells without paying their mana costs until end of turn.

Harmony — Draw a card.
When Enthralling Actor enters, harmonize. (Trigger up to one harmony of one permanent you control.)

Enchant creature
You control enchanted creature.
Enchanted creature gets +1/+1 and has slipstream. (This creature can't be blocked as long as only creatures with slipstream are attacking.)

You may have Ephemeral Qilin enter as a copy of a multicolored permanent you control.