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

Entirely Normal Armchair

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

Planar Nexus

This land is every nonbasic land type. (Nonbasic land types include Cave, Desert, Gate, Lair, Locus, Mine, Power-Plant, Sphere, Tower, and Urza's.)
{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Staff of the Letter Magus

As this artifact enters, choose a consonant other than N, R, S, or T.
Whenever a player casts a spell, you gain 1 life for each time the chosen letter appears in that spell's name.

Creature Guy

Gotcha — If an opponent says "creature" or "guy," you may say "Gotcha!" When you do, return Creature Guy from your graveyard to your hand.

Double Take

Choose another player. You draw two cards. At the beginning of the first upkeep in your next game with that player, you draw two cards.

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.

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 this card 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.

Mox Lotus

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

Double Deal

Choose another player. Double Deal deals 3 damage to that player. At the beginning of the first upkeep in your next game with that player, Double Deal deals 3 damage to the player.

Island

Mountain

Forest

Gleemax

You choose all targets for all spells and abilities.

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.

Underdome

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

Sorry

Before any player casts a spell with the same name as a card in any graveyard, that player may say "sorry." If they don't, any other player may say "sorry" as the spell is being cast. When another player says "sorry" this way, counter the spell.
Whenever a player says "sorry" at any other time, Sorry deals 2 damage to that player.

My First Tome

{1}, {T}: Say the flavor text on a card in your hand. Target opponent guesses that card's name. You may reveal that card. If you do and they guessed wrong, you draw a card.

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.)
This land enters tapped.
When this land enters, sacrifice it unless you pay {1}.

Double Play

Choose another player. Search your library for a basic land card, put it onto the battlefield, then shuffle. At the beginning of the first upkeep in your next game with that player, search your library for a basic land card, put it onto the battlefield, then shuffle.