Navigation Orb

{2}, {T}, Sacrifice Navigation Orb: Search your library for up to two basic land cards and/or Gate cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Cloud Key

As Cloud Key enters the battlefield, choose artifact, creature, enchantment, instant, or sorcery.
Spells you cast of the chosen type cost {1} less to cast.

Mountain

Strionic Resonator

{2}, {T}: Copy target triggered ability you control. You may choose new targets for the copy. (A triggered ability uses the words "when," "whenever," or "at.")

Rupture Spire

Rupture Spire enters the battlefield tapped.
When Rupture Spire enters the battlefield, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Grand Coliseum

Grand Coliseum enters the battlefield tapped.
{T}: Add {C}.
{T}: Add one mana of any color. Grand Coliseum deals 1 damage to you.

Archway Commons

Archway Commons enters the battlefield tapped.
When Archway Commons enters the battlefield, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Mirrodin's Core

{T}: Add {C}.
{T}: Put a charge counter on Mirrodin's Core.
{T}, Remove a charge counter from Mirrodin's Core: Add one mana of any color.

Worn Powerstone

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

Sol Ring

Transguild Promenade

Transguild Promenade enters the battlefield tapped.
When Transguild Promenade enters the battlefield, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Burnished Hart

{3}, Sacrifice Burnished Hart: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Ur-Golem's Eye

Doubling Cube

{3}, {T}: Double the amount of each type of unspent mana you have.

Urza's Tower

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

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 Mine

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

Stonespeaker Crystal

{T}: Add {C}{C}.
{2}, {T}, Sacrifice Stonespeaker Crystal: Exile any number of target players' graveyards. Draw a card.

Public Thoroughfare

Public Thoroughfare enters the battlefield tapped.
When Public Thoroughfare enters the battlefield, sacrifice it unless you tap an untapped artifact or land you control.
{T}: Add one mana of any color.

Gateway Plaza

Gateway Plaza enters the battlefield tapped.
When Gateway Plaza enters the battlefield, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Discord, Lord of Disharmony

Flying
At the beginning of your end step, choose a random nonland Magic card name. Until your next end step, you may cast a copy of a spell with that name, and mana of any type can be spent to cast it. If you cast a spell this way, copy this ability if Discord is on the battlefield.

Hedron Archive

{T}: Add {C}{C}.
{2}, {T}, Sacrifice Hedron Archive: Draw two cards.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Sisay's Ring

Ichor Elixir

If you would roll one or more planar dice, instead roll that many planar dice plus one and ignore one.
{T}: Add {C}{C}.

Dreamstone Hedron

{T}: Add {C}{C}{C}.
{3}, {T}, Sacrifice Dreamstone Hedron: Draw three cards.

Thran Dynamo

Roaming Throne

Ward {2}
As Roaming Throne enters the battlefield, choose a creature type.
Roaming Throne is the chosen type in addition to its other types.
If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

Champion's Helm

Equipped creature gets +2/+2.
As long as equipped creature is legendary, it has hexproof. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Forbidden Orchard

{T}: Add one mana of any color.
Whenever you tap Forbidden Orchard for mana, target opponent creates a 1/1 colorless Spirit creature token.

Lithoform Engine

{2}, {T}: Copy target activated or triggered ability you control. You may choose new targets for the copy.
{3}, {T}: Copy target instant or sorcery spell you control. You may choose new targets for the copy.
{4}, {T}: Copy target permanent spell you control. (The copy becomes a token.)