Mana Web

Whenever a land an opponent controls is tapped for mana, tap all lands that player controls that could produce any type of mana that land could produce.

Phyrexian Colossus

Phyrexian Colossus doesn't untap during your untap step.
Pay 8 life: Untap Phyrexian Colossus.
Phyrexian Colossus can't be blocked except by three or more creatures.

Ancient Tomb

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Karn, Silver Golem

Whenever Karn, Silver Golem blocks or becomes blocked, it gets -4/+4 until end of turn.
{1}: Target noncreature artifact becomes an artifact creature with power and toughness each equal to its mana value until end of turn.

Mountain

Wildfire

Each player sacrifices four lands. Wildfire deals 4 damage to each creature.

Fire Diamond

Fire Diamond enters tapped.
{T}: Add {R}.

Winter Orb

As long as Winter Orb is untapped, players can't untap more than one land during their untap steps.

Worn Powerstone

Worn Powerstone enters tapped.
{T}: Add {C}{C}.

Voltaic Key

Mishra's Helix

Flametongue Kavu

When Flametongue Kavu enters, it deals 4 damage to target creature.

Masticore

At the beginning of your upkeep, sacrifice Masticore unless you discard a card.
{2}: Masticore deals 1 damage to target creature.
{2}: Regenerate Masticore.

Mudslide

Creatures without flying don't untap during their controllers' untap steps.
At the beginning of each player's upkeep, that player may choose any number of tapped creatures without flying they control and pay {2} for each creature chosen this way. If the player does, untap those creatures.

Thran Dynamo

Temporal Aperture

{5}, {T}: Shuffle your library, then reveal the top card. Until end of turn, for as long as that card remains on top of your library, play with the top card of your library revealed and you may play that card without paying its mana cost. (If it has X in its mana cost, X is 0.)

Covetous Dragon

Flying
When you control no artifacts, sacrifice Covetous Dragon.

Rishadan Port

Cursed Scroll

{3}, {T}: Choose a card name, then reveal a card at random from your hand. If that card has the chosen name, Cursed Scroll deals 2 damage to any target.