The Seventh Doctor

Whenever The Seventh Doctor attacks, choose a card in your hand. Defending player guesses whether that card's mana value is greater than the number of artifacts you control. If they guessed wrong, you may cast it without paying its mana cost. If you don't cast a spell this way, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

The Celestial Toymaker

Whenever The Celestial Toymaker attacks, look at the top three cards of your library. Exile any number of them in a face-down pile and the rest in a face-up pile. Defending player chooses one of those piles. Put that pile into your hand.
At the beginning of each end step, each opponent loses 2 life for each spell or ability that caused one or more players to guess or to group cards or permanents into a pile this turn.

Delney, Streetwise Lookout

Creatures you control with power 2 or less can't be blocked by creatures with power 3 or greater.
If an ability of a creature you control with power 2 or less triggers, that ability triggers an additional time.

MacCready, Lamplight Mayor

Whenever a creature you control with power 2 or less attacks, it gains skulk until end of turn. (It can't be blocked by creatures with greater power.)
Whenever a creature with power 4 or greater attacks you, its controller loses 2 life and you gain 2 life.

Fact or Fiction

Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Intrude on the Mind

Reveal the top five cards of your library and separate them into two piles. An opponent chooses one of those piles. Put that pile into your hand and the other into your graveyard. Create a 0/0 colorless Thopter artifact creature token with flying, then put a +1/+1 counter on it for each card put into your graveyard this way.

Ghastly Conscription

Exile all creature cards from target player's graveyard in a face-down pile, shuffle that pile, then manifest those cards. (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.)

Truth or Tale

Reveal the top five cards of your library and separate them into two piles. An opponent chooses one of those piles. Put a card from the chosen pile into your hand, then put all other cards revealed this way on the bottom of your library in any order.

Sphinx of Clear Skies

Flying, ward {2}
Domain — Whenever Sphinx of Clear Skies deals combat damage to a player, reveal the top X cards of your library, where X is the number of basic land types among lands you control. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard. (Piles can be empty.)

The Second Doctor

Players have no maximum hand size.
How Civil of You — At the beginning of your end step, each player may draw a card. Each opponent who does can't attack you or permanents you control during their next turn.

Brotherhood Regalia

Equipped creature has ward {2}, is an Assassin in addition to its other types, and can't be blocked.
Equip legendary creature {1}
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Auton Soldier

You may have Auton Soldier enter as a copy of any creature on the battlefield, except it isn't legendary, is an artifact in addition to its other types, and has myriad. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

Triumph of Saint Katherine

Lifelink
Praesidium Protectiva — When Triumph of Saint Katherine is put into your graveyard from the battlefield, exile it and the top six cards of your library in a face-down pile. If you do, shuffle that pile and put it back on top of your library.
Miracle {1}{W} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

Epiphany at the Drownyard

Reveal the top X plus one cards of your library and separate them into two piles. An opponent chooses one of those piles. Put that pile into your hand and the other into your graveyard.

Become Anonymous

Exile target nontoken creature you own and the top two cards of your library in a face-down pile, shuffle that pile, then cloak those cards. They enter tapped. (To cloak a card, put it onto the battlefield face down as a 2/2 creature with ward {2}. Turn it face up any time for its mana cost if it's a creature card.)

Death or Glory

Separate all creature cards in your graveyard into two piles. Exile the pile of an opponent's choice and return the other to the battlefield.

Fortune's Favor

Target opponent looks at the top four cards of your library and separates them into a face-down pile and a face-up pile. Put one pile into your hand and the other into your graveyard.

Sphinx of Uthuun

Flying
When Sphinx of Uthuun enters, reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Sauron's Ransom

Choose an opponent. They look at the top four cards of your library and separate them into a face-down pile and a face-up pile. Put one pile into your hand and the other into your graveyard. The Ring tempts you.

Make an Example

Each opponent separates the creatures they control into two piles. For each opponent, you choose one of their piles. Each opponent sacrifices the creatures in their chosen pile. (Piles can be empty.)

Master of Ceremonies

At the beginning of your upkeep, each opponent chooses money, friends, or secrets. For each player who chose money, you and that player each create a Treasure token. For each player who chose friends, you and that player each create a 1/1 green and white Citizen creature token. For each player who chose secrets, you and that player each draw a card.

Unesh, Criosphinx Sovereign

Flying
Sphinx spells you cast cost {2} less to cast.
Whenever Unesh, Criosphinx Sovereign or another Sphinx you control enters, reveal the top four cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Spark Double

You may have Spark Double enter as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Hostile Negotiations

Exile the top three cards of your library in a face-down pile, then exile the top three cards of your library in another face-down pile. Look at the cards in each pile, then turn a pile of your choice face up. An opponent chooses one of those piles. Put that pile into your hand and the other into your graveyard. You lose 3 life.

Brilliant Ultimatum

Exile the top five cards of your library. An opponent separates those cards into two piles. You may play lands and cast spells from one of those piles. If you cast a spell this way, you cast it without paying its mana cost.

Liar's Pendulum

{2}, {T}: Choose a card name. Target opponent guesses whether a card with that name is in your hand. You may reveal your hand. If you do and your opponent guessed wrong, draw a card.

Gollum, Scheming Guide

Whenever Gollum, Scheming Guide attacks, look at the top two cards of your library, put them back in any order, then choose land or nonland. An opponent guesses whether the top card of your library is the chosen kind. Reveal that card. If they guessed right, remove Gollum from combat. Otherwise, you draw a card and Gollum can't be blocked this turn.

Master of Predicaments

Flying
Whenever Master of Predicaments deals combat damage to a player, choose a card in your hand. That player guesses whether the card's mana value is greater than 4. If the player guessed wrong, you may cast the card without paying its mana cost.

Atris, Oracle of Half-Truths

Menace
When Atris, Oracle of Half-Truths enters, target opponent looks at the top three cards of your library and separates them into a face-down pile and a face-up pile. Put one pile into your hand and the other into your graveyard.

Boneyard Parley

Exile up to five target creature cards from graveyards. An opponent separates those cards into two piles. Put all cards from the pile of your choice onto the battlefield under your control and the rest into their owners' graveyards.

Fight or Flight

At the beginning of combat on each opponent's turn, separate all creatures that player controls into two piles. Only creatures in the pile of their choice can attack this turn.

Do or Die

Separate all creatures target player controls into two piles. Destroy all creatures in the pile of that player's choice. They can't be regenerated.

Jace, Architect of Thought

+1: Until your next turn, whenever a creature an opponent controls attacks, it gets -1/-0 until end of turn.
−2: Reveal the top three cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other on the bottom of your library in any order.
−8: For each player, search that player's library for a nonland card and exile it, then that player shuffles. You may cast those cards without paying their mana costs.

The Toymaker's Trap

At the beginning of your upkeep, secretly choose a number between 1 and 5 that hasn't been chosen. If you do, an opponent guesses which number you chose, then you reveal the number you chose. If they guessed wrong, they lose life equal to the number they guessed and you draw a card. If they guessed right, sacrifice The Toymaker's Trap.