Gleemax

You choose all targets for all spells and abilities.

Sly Spy

Whenever Sly Spy deals combat damage to a player, that player loses a finger until Sly Spy leaves the battlefield. (The finger is chosen by its owner and can't roll dice or touch cards.)

Whenever Sly Spy deals combat damage to a player, that player reveals the top card of their library. Put that card into your hand and you lose life equal to its mana value.

Kindslaver

{5}, {T}, Sacrifice Kindslaver: A person outside the game controls target player during that player's next turn. Neither player may advise that person until the end of that turn.

Clocknapper

When Clocknapper enters, choose beginning phase, first main phase, combat phase, second main phase, or ending phase. Steal that phase from target player during their next turn. (That phase occurs as though it's your turn instead.)

Graveyard Busybody

All graveyards are also your graveyards.
Graveyard Busybody's power and toughness are each equal to the number of cards with flavor text in your graveyards.

Entirely Normal Armchair

During your turn, if Entirely Normal Armchair is in your hand, you may hide it on the battlefield.
{0}: Return Entirely Normal Armchair to its owner's hand. Only your opponents may activate this ability and only if they see Entirely Normal Armchair.
{2}, Sacrifice Entirely Normal Armchair: Destroy target attacking creature.

Over My Dead Bodies

Creature cards in graveyards can attack and block as though they were on the battlefield, can block or be blocked only by creature cards in graveyards, are Zombies in addition to their other types, and have undeathtouch. (If they would deal damage to a creature card, exile that creature card instead.)
Creature cards in your graveyard have haste.

As long as X is in X's owner's opponent's hand, X's owner may cast X and activate X's abilities. That opponent can't cast X and plays with their hand revealed.
{U}{B}, {T}: Put X into target opponent's hand.
{3}{U}{B}: You may play a land or cast a spell from the hand X is in. If you cast a spell this way, you cast it without paying its mana cost.

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.

Hangman

As Hangman enters, secretly note a word with six to eight letters.
{1}: Target player who doesn't control Hangman guesses the noted word or an unguessed letter in that word. If they guess wrong, put a +1/+1 counter on Hangman. Any player may activate this ability.
When a player guesses the noted word or all of its letters, sacrifice Hangman.

Masterful Ninja

Haste
Reveal Masterful Ninja from your hand: Masterful Ninja is on the battlefield and in your hand until end of turn.
{1}{B}: Masterful Ninja gets +1/+1 until end of turn.

Modular Monstrosity

Whenever an opponent casts a spell, you have five seconds to choose a keyword you haven't chosen for a card named Modular Monstrosity today that's been printed on a creature card. If you do, Modular Monstrosity gains that ability. Otherwise, Modular Monstrosity loses all keyword abilities.

Old-Fashioned Vampire

Flying
Old-Fashioned Vampire gets +2/+2 and has deathtouch as long as it's dark outdoors.

The Countdown Is at One

Players play a Magic subgame, starting at 1 life and using their libraries as their decks. For the rest of the main game, if a source would deal damage to a player who didn't win the subgame, it deals double that damage to that player instead.

Baron Von Count

Baron Von Count enters with a doom counter on "5."
Whenever you cast a spell with the indicated numeral in its mana cost, text box, power, or toughness, move the doom counter one numeral to the left.
When the doom counter moves from "1," destroy target player and put that doom counter on "5."

Spy Eye

Flying
Whenever Spy Eye deals combat damage to a player, you may draw a card from that player's library.

More or Less

Add or subtract 1 or one from a number or number word on target spell or permanent until end of turn.

Just Desserts

Just Desserts deals π damage to target creature. (π is the ratio of a circle's circumference to its diameter. (It's a smidgen more than 3.))

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.

Magic Word

Enchant creature
As Magic Word enters, choose a word.
Whisper the chosen word: Tap enchanted creature.

It That Gets Left Hanging

When It That Gets Left Hanging enters, ask a person outside the game to high-five you. If they won't, It That Gets Left Hanging gains haste until end of turn.

Devil K. Nevil

Haste
When Devil K. Nevil enters, jump it over any number of creatures. If it clears those creatures, put that many +1/+1 counters on it. (You can see a jumping demonstration at DevilKNevil.com.)

Animate Graveyard

Enchant your graveyard
Enchanted graveyard is a creature on the battlefield with base power and toughness each equal to the number of cards in it. It has the text boxes of all creature cards in it. It's still a graveyard.
If enchanted graveyard would leave the battlefield, instead exile Animate Graveyard.

Trigger Happy

Choose a triggered ability of target permanent. It triggers. You control that ability.

A Real Handful

As long as one or more hands are touching A Real Handful, it gets +2/+2.
As long as two or more hands are touching A Real Handful, it has menace.
As long as three or more hands are touching A Real Handful, it has lifelink.

Octo Opus

When Octo Opus enters, create a 4/4 blue Octopus Performer creature token named Contortionist with "At the beginning of your upkeep, you may fold this token in half." (It becomes 2/2, then 1/1, ½/½, and so on.)
Sacrifice Octo Opus: Draw a card and an additional card for each of Contortionist's folds.

Super-Duper Lost

Put target creature into its owner's library just beneath the top X cards of that library, where X is the number of doors you can see from your seat.

Amped Up

This spell costs {1} less to cast for each electrical socket in a wall or floor you can see from your seat.
Gain control of target creature until end of turn. Untap that creature. Until end of turn, it gets +3/+0 and gains haste.

Bag Check

Counter target spell, then ask a person outside the game if that spell looks dangerous to them. If they say yes, draw a card, then discard a card.

Truss, Chief Engineer

Whenever Truss, Chief Engineer enters or another creature dies, put a hack counter on Truss.
{2}, {T}, Remove X hack counters from Truss: Add or subtract X from a number or number word on target spell or permanent until end of turn. This effect can't reduce a number below 1 or a number word below one.

Standard Procedure

{1}, Reveal Standard Procedure from your hand: Choose an instant or sorcery card with mana value 3 or less currently legal in the Standard format. Standard Procedure becomes that card until end of turn.

Water Gun Balloon Game

As Water Gun Balloon Game enters, each player puts a pop! counter on "0."
Whenever a player casts a spell, move that player's pop! counter up one.
Whenever a player's pop! counter hits "5," that player creates a 5/5 pink Giant Teddy Bear creature token and resets all pop! counters to "0."

D00-DL, Caricaturist

When D00-DL, Caricaturist enters, create a 4/4 colorless Sketch creature token, which you have fifteen seconds to draw. The token has flying if it has wings in its art. The same is true for first strike and a sword, vigilance and a shield, menace and mean eyes, trample and horns, deathtouch and claws, lifelink and fangs, and haste and footwear.

Urza's Fun House

{T}: Add {C}.
{T}: Add {∞}. Activate only once and only if you control an Urza's Mine, an Urza's Power-Plant, and an Urza's Tower.
{7}, {T}: Head to AskUrza.com and click Urza's Fun House.

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.

Alexander Clamilton

Whenever you cast a wordy spell, scry 2. (A spell is wordy if it has four or more lines of rules text.)
{1}{R}, {T}: Choose target creature you don't control. Reveal the top card of your library. Alexander Clamilton gets +X/+0 until end of turn, where X is the number of lines of rules text of the revealed card. Alexander Clamilton fights that creature.

Boomstacker

As Boomstacker enters and whenever it attacks, stack two dice on top of it. (All dice must be stacked vertically, one on top of another.)
Boomstacker gets +1/+1 for each die in its stack.
Boomstacker attacks each combat if able.
When the stack falls, sacrifice Boomstacker.

Enter the Dungeon

Players play a Magic subgame under the table, starting at 5 life and using their libraries as their decks. The winner searches their library for two cards, puts those cards into their hand, then shuffles.

Rings a Bell

As Rings a Bell enters, choose a word with four or more letters.
After you say the chosen word for the first time each turn, an opponent may ring or imitate a bell within five seconds. When no opponent does, draw a card.

Infernal Spawn of Evil

Flying, first strike
{1}{B}, Reveal Infernal Spawn of Evil from your hand, Say "It's coming!": Infernal Spawn of Evil deals 1 damage to target opponent or planeswalker. Activate only during your upkeep and only once each turn.

Johnny, Combo Player

{4}: Search your library for a card, put that card into your hand, then shuffle.

Strategy, Schmategy

Roll a six-sided die. Strategy, Schmategy has the indicated effect.
1 — Do nothing.
2 — Destroy all artifacts.
3 — Destroy all lands.
4 — Strategy, Schmategy deals 3 damage to each creature and each player.
5 — Each player discards their hand and draws seven cards.
6 — Repeat this process two more times.

Booster Tutor

Open a sealed Magic booster pack, reveal the cards, and put one of them into your hand. (Remove that card from your deck before beginning a new game.)

Yet Another Aether Vortex

All creatures have haste.
Players play with the top card of their libraries revealed.
Noninstant, nonsorcery cards on top of a library are on the battlefield under their owner's control in addition to being in that library.

Richard Garfield, Ph.D.

You may play cards as though they were other cards of your choice with the same mana cost. You can't choose the same card twice. (Mana cost includes color.)

Topsy Turvy

The phases of each player's turn are reversed. (The phases are, in reverse order, ending, second main, combat, first main, and beginning.)
As long as there are more than two players in the game, the turn order is reversed.

Six-y Beast

As Six-y Beast enters, you secretly put six or fewer +1/+1 counters on it, then an opponent guesses the number of counters. If that player guesses right, sacrifice Six-y Beast after it enters.

Destroy target creature with reminder text. (Reminder text is any italicized text in parentheses that explains rules you already know.)

Pointy Finger of Doom

{3}, {T}: Spin Pointy Finger of Doom in the middle of the table so that it rotates completely at least once, then destroy the closest permanent the finger points to.

Underdome

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to pay Un-costs.

Kill! Destroy!

Destroy target nonblack creature.
Gotcha — If an opponent says "kill" or "destroy," you may say "Gotcha!" When you do, return Kill! Destroy! from your graveyard to your hand.

Deal Damage

Deal Damage deals 4 damage to any target.
Gotcha — If an opponent says "deal" or "damage," you may say "Gotcha!" When you do, return Deal Damage from your graveyard to your hand.

Spell Counter

Counter target spell.
Gotcha — If an opponent says "spell" or "counter," you may say "Gotcha!" When you do, return Spell Counter from your graveyard to your hand.

Eye to Eye

You and target creature's controller have a staring contest. If you win, destroy that creature.

Face to Face

You and target opponent play a best two-out-of-three Rock, Paper, Scissors match. If you win, Face to Face deals 5 damage to that player.

Mouth to Mouth

Choose target opponent and target creature they control. You and that player have a breath-holding contest. If you win, you gain control of that creature.

Number Crunch

Return target permanent to its owner's hand.
Gotcha — If an opponent says a number, you may say "Gotcha!" When you do, return Number Crunch from your graveyard to your hand.

Avatar of Me

This spell costs {1} more to cast for each ten years you've been alive.
Avatar of Me's power is equal to your height in feet and its toughness is equal to your American shoe size. Round to the nearest ½.
Avatar of Me is the color of your eyes.

Frazzled Editor

Protection from wordy (Something is wordy if it has four or more lines of rules text.)

Bursting Beebles

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

Farewell to Arms

As Farewell to Arms enters, choose a hand attached to an opponent's arm.
When the chosen hand isn't behind its owner's back, sacrifice Farewell to Arms. If you do, that player discards their hand . . . of cards. (The lawyers wouldn't let us do it the other way.)

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

Red-Hot Hottie

Whenever Red-Hot Hottie deals damage to a creature, put a third-degree-burn counter on that creature. It gains "At the beginning of each end step, sacrifice this creature unless you scream 'Aaah!' at the top of your lungs."

Rocket-Powered Turbo Slug

Super haste (This may attack the turn before you cast it. (You may put this card from your hand onto the battlefield tapped and attacking during your declare attackers step. If you do, you lose the game at the beginning of your next turn's end step unless you pay this card's mana cost during that turn.))

Letter Bomb

When Letter Bomb enters, sign it and shuffle it into target player's library. That player reveals each card they draw until they draw Letter Bomb. When that player draws Letter Bomb, it deals 19½ damage to them.

Mox Lotus

{T}: Add {∞}.
{100}: Add one mana of any color.

City of Ass

City of Ass enters tapped.
{T}: Add one and one-half mana of any one color.

Nearby Planet

Rangeling (This card is every land type, including Plains, Island, Swamp, Mountain, Forest, Desert, Gate, Lair, Locus, and all those Urza's ones.)
Nearby Planet enters tapped.
When Nearby Planet enters, sacrifice it unless you pay {1}.

The Big Top

{T}: Add one mana of any color that appears on your top. (A top is an outerwear garment worn on the upper body.)

Command Tower

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

Crumbling Necropolis

Crumbling Necropolis enters tapped.
{T}: Add {U}, {B}, or {R}.

Xander's Lounge

({T}: Add {U}, {B}, or {R}.)
Xander's Lounge enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Dragonskull Summit

Dragonskull Summit enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Sulfur Falls

Sulfur Falls enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Drowned Catacomb

Drowned Catacomb enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Seething Landscape

{T}: Add {C}.
{T}, Sacrifice Seething Landscape: Search your library for a basic Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.
Cycling {U}{B}{R} ({U}{B}{R}, Discard this card: Draw a card.)

Path of Ancestry

Path of Ancestry enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Stormcarved Coast

Stormcarved Coast enters tapped unless you control two or more other lands.
{T}: Add {U} or {R}.