Cheatyface

If Cheatyface is in your hand, you may sneak Cheatyface onto the battlefield. If an opponent catches you right away, that player may exile Cheatyface.
Flying

Killer Cosplay

Whenever Killer Cosplay becomes attached to a creature, choose a creature card name with an identical mana cost. That creature becomes a copy of the card with the chosen name until Killer Cosplay becomes unattached from it.
Equip {3}

Checks and Balances

Cast this spell only if there are three or more players in the game.
Whenever a player casts a spell, each of that player's opponents may discard a card. If they do, counter that spell.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Island

Bureaucracy

Pursuant to subsection 3.1(4) of Richard's Rules of Order, at the beginning of the upkeep of each participant in this game of the Magic: The Gathering® trading card game (hereafter known as "PLAYER"), that PLAYER performs all actions in the sequence of previously added actions (hereafter known as "ACTION QUEUE"), in the order those actions were added, then adds another action to the end of the ACTION QUEUE. All actions must be simple physical or verbal actions that a player can perform while sitting in a chair, without jeopardizing the health and security of said PLAYER.
When any PLAYER does not perform all the prescribed actions in the correct order, sacrifice Bureaucracy and said PLAYER discards their complement of cards in hand (hereafter known as "HAND").

Simic Cluestone

{T}: Add {G} or {U}.
{G}{U}, {T}, Sacrifice Simic Cluestone: Draw a card.

The Sixth Doctor

Time Lord's Prerogative — Whenever you cast a historic spell, copy it, except the copy isn't legendary. This ability triggers only once each turn. (Artifacts, legendaries, and Sagas are historic. A copy of a permanent spell becomes a token.)

Sky Diamond

Moss Diamond

Moss Diamond enters tapped.
{T}: Add {G}.

Simic Signet

Forest

Boing!

Return target creature to its owner's hand, then roll a six-sided die. If the result is 3 or less, scry a number of cards equal to the result.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Animate Library

Enchant your library
Enchanted library is an artifact creature on the battlefield with power and toughness each equal to the number of cards in it. It's still a library.
If enchanted library would leave the battlefield, exile Animate Library instead.

Blufferfish

{3}{U}: An opponent tells you a statement about themselves and secretly notes whether it's true or false. You guess which it is. If you guessed correctly, Blufferfish gets +2/+0 and can't be blocked this turn.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

B.O.B. (Bevy of Beebles)

As B.O.B. enters, create four 1/1 blue Beeble creature tokens.
The number of loyalty counters on B.O.B. is equal to the number of Beebles you control. (Create or sacrifice Beebles whenever B.O.B. gains or loses loyalty.)
+1: Up to X target Beebles can't be blocked this turn, where X is the number of cards in your hand.
−1: Draw a card.

Command Tower

Replicate

Create a token that's a copy of target creature you control.

Repudiate

Counter target activated or triggered ability. (Mana abilities can't be targeted.)

Repudiate // Replicate

Bursting Beebles

Bursting Beebles can't be blocked as long as defending player controls two or more nonland permanents that share an artist.

It Came from Planet Glurg

You may have It Came from Planet Glurg enter as a copy of X different creatures on the battlefield. (It has their total power, total toughness, combined mana costs, all text boxes, names, art, and so on.)

Clam Session

As Clam Session enters, choose a word.
At the beginning of your upkeep, you may sing at least six words of a song, at least one of which is the chosen word. If you don't, sacrifice Clam Session. You can't repeat a song.

Carnivorous Death-Parrot

Flying
At the beginning of your upkeep, sacrifice Carnivorous Death-Parrot unless you say its flavor text.

Tamiyo, Compleated Sage

Compleated ({G/U/P} can be paid with {G}, {U}, or 2 life. If life was paid, this planeswalker enters with two fewer loyalty counters.)
+1: Tap up to one target artifact or creature. It doesn't untap during its controller's next untap step.
−X: Exile target nonland permanent card with mana value X from your graveyard. Create a token that's a copy of that card.
−7: Create Tamiyo's Notebook, a legendary colorless artifact token with "Spells you cast cost {2} less to cast" and "{T}: Draw a card."

Sol Ring

Blurry Beeble

Blurry (This creature can be blocked only if defending player was wearing glasses as it was cast.)
Whenever Blurry Beeble deals combat damage to a player, you may draw a card. If you do, discard a card.

Busted!

Counter target spell unless its controller pays {X}, where X is the number of words in the name with the most words among permanents you control.

Artful Looter

{T}: Draw a card, then discard a card.
Whenever a permanent that shares an artist with another permanent you control enters, untap Artful Looter.

Mobile Clone

Using a mobile device, take a picture of target creature. That device enters as a token that's a photocopy of the pictured creature. (Photocopies include Auras, Equipment, counters, and stickers in the shot. Don't touch other people's phones without permission and be careful if you do.)

Simic Keyrune

{T}: Add {G} or {U}.
{G}{U}: Simic Keyrune becomes a 2/3 green and blue Crab artifact creature with hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Double Major

Copy target creature spell you control, except it isn't legendary if the spell is legendary. (A copy of a creature spell becomes a token.)

Censorship

As Censorship enters, choose a word.
Whenever a player says the chosen word, Censorship deals 2 damage to that player.

Altered Ego

This spell can't be countered.
You may have Altered Ego enter as a copy of any creature on the battlefield, except it enters with X additional +1/+1 counters on it.

Progenitor Mimic

You may have Progenitor Mimic enter as a copy of any creature on the battlefield, except it has "At the beginning of your upkeep, if this creature isn't a token, create a token that's a copy of this creature."