Urza's Power Plant

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

Ivory Tower

At the beginning of your upkeep, you gain X life, where X is the number of cards in your hand minus 4.

Mishra's Workshop

{T}: Add {C}{C}{C}. Spend this mana only to cast artifact spells.

Urza's Tower

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

Colossus of Sardia

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Colossus of Sardia doesn't untap during your untap step.
{9}: Untap Colossus of Sardia. Activate only during your upkeep.

Candelabra of Tawnos

Sentinel

{0}: Change Sentinel's base toughness to 1 plus the power of target creature blocking or blocked by Sentinel. (This effect lasts indefinitely.)

Urza's Mine

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

Metalworker

{T}: Reveal any number of artifact cards in your hand. Add {C}{C} for each card revealed this way.

Mishra's Factory

{T}: Add {C}.
{1}: Mishra's Factory becomes a 2/2 Assembly-Worker artifact creature until end of turn. It's still a land.
{T}: Target Assembly-Worker creature gets +1/+1 until end of turn.

Clay Statue

Reflecting Mirror

{X}, {T}: Change the target of target spell with a single target if that target is you. The new target must be a player. X is twice the mana value of that spell.

Aladdin's Lamp

{X}, {T}: The next time you would draw a card this turn, instead look at the top X cards of your library, put all but one of them on the bottom of your library in a random order, then draw a card. X can't be 0.

Library of Leng

You have no maximum hand size.
If an effect causes you to discard a card, discard it, but you may put it on top of your library instead of into your graveyard.

Rocket Launcher

{2}: Rocket Launcher deals 1 damage to any target. Destroy Rocket Launcher at the beginning of the next end step. Activate only if you've controlled Rocket Launcher continuously since the beginning of your most recent turn.