msem-instigator

Look at the top two cards of your library. Put one of them into your hand, then you may have any number of players each mill three cards.

When Undead Archivist enters, return target instant or sorcery card from your graveyard to your hand.
Revive {5}{U} ({5}{U}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

You may have Undecided Mimic enter or phase in as a copy of any creature on the battlefield, except it has this ability and “{2}{U}{U}: Undecided Mimic phases out.” (Treat it and anything attached to it as though they don't exist until its controller's next turn.)

If you've scried this turn, this spell costs {2} less to cast and can't be countered.
Draw two cards.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)

Whenever a creature you control dies, you may return all cards that were inscribed onto that creature and all Auras that were attached to that creature to their owners' hands.

Ungoverned Sneak can't be blocked by creatures with greater power.
Attain {3}{U} ({3}{U}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

If you would draw a card, you may return an instant or sorcery card from your graveyard to your hand instead.
{U}: Draw three cards.

Whenever you cast a noncreature spell, create a 1/1 colorless Construct artifact creature token.

Each artifact you control has all the activated abilities of other artifacts you control.

Conjure six duplicates of target instant or sorcery card in a graveyard into your main library. Then shuffle.
Draw a card.

Gain control of target creature with power less than or equal to the number of different creature types among creatures you control.

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)
Tap up to three target creatures. If this spell was kicked, those creatures don't untap during their controller's next untap step.

Counter target spell if four or more mana was spent to cast it.

Choose one, then choose another for each card named Unraveling in your graveyard.
• Counter up to one target spell.
• Scry 2, then draw a card.
• Up to three target lands your opponents control don't untap during their controller's next untap step.
• Creatures your opponents control get -4/-0 until end of turn.

Flying
When Unraveller of Mysteries enters, mill two cards.

Discard a card: Unseen Maniac gets +1/+1 and can't be blocked this turn.
Whenever Unseen Maniac deals combat damage to a player, draw a card.

Rhapsody {4}{U}{U} (Pay {4}{U}{U} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
When Unstable Prophet enters, surveil X, where X is its power. (Look at the top X cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Return target creature to its owner's hand.

Look at target opponent's hand, then fateseal 1. (To fateseal 1, look at the top card of an opponent's library, then you may put it on the bottom of that player's library.)

Target creature gets -9/-0 until end of turn. Create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
When Ushi Yun enters, create an Idol token.
As long as you're in a renaissance, artifacts you control have “{T}: Draw a card.”

Foretell {X}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)
Gain control of target creature with power 2 or less. If this spell was foretold, gain control of target creature with power X or less instead.

As Vaertris' Master Plan enters, exile the top five cards of any player's library.
You may play cards exiled with Vaertris' Master Plan.
When there are no cards exiled with Vaertris' Master Plan, return it to its owner's hand.

[+1]: Until end of turn, whenever target creature deals combat damage to a player, that player mills two cards.
[–1]: Tap target creature. It can't become untapped for as long as you control Vaertris, Mindmelder.
[–6]: You get an emblem with “Whenever you draw a card, target player mills three cards” and “{2}{U}: Draw a card.”