Letter Bomb

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

Urza's Tower

{T}: Add {C}. If you control an Urza's Mine and an Urza's Power-Plant, add {C}{C}{C} instead.

Mox Lotus

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

Buzzing Whack-a-Doodle

As this artifact enters, you and an opponent each secretly choose Whack or Doodle. Then those choices are revealed. If the choices match, this artifact has that ability. Otherwise, it has Buzz.
• Whack — {T}: Target player loses 2 life.
• Doodle — {T}: You gain 3 life.
• Buzz — {2}, {T}: Draw a card.

Gleemax

You choose all targets for all spells and abilities.

Urza's Hot Tub

{2}, Discard a card: Search your library for a card that shares a complete word in its name with the discarded card, reveal it, put it into your hand, then shuffle.

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.

Urza's Cave

{T}: Add {C}.
{3}, {T}, Sacrifice this land: Search your library for a land card, put it onto the battlefield tapped, then shuffle.

Bosh, Iron Golem

Trample
{3}{R}, Sacrifice an artifact: Bosh deals damage equal to the sacrificed artifact's mana value to any target.

Urza's Mine

{T}: Add {C}. If you control an Urza's Power-Plant and an Urza's Tower, add {C}{C} instead.

Inventors' Fair

At the beginning of your upkeep, if you control three or more artifacts, you gain 1 life.
{T}: Add {C}.
{4}, {T}, Sacrifice Inventors' Fair: Search your library for an artifact card, reveal it, put it into your hand, then shuffle. Activate only if you control three or more artifacts.

Steel Squirrel

Whenever you roll a 5 or higher on a die, this creature gets +X/+X until end of turn, where X is the result.
{6}: Roll a six-sided die.

Rod of Spanking

{2}, {T}: This artifact deals 1 damage to target player. Then untap this artifact unless that player says "Thank you, sir. May I have another?"

Urza's Power Plant

{T}: Add {C}. If you control an Urza's Mine and an Urza's Tower, add {C}{C} instead.

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.