Training Center

Training Center enters tapped unless you have two or more opponents.
{T}: Add {U} or {R}.

Glacial Fortress

Glacial Fortress enters tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Hallowed Fountain

({T}: Add {W} or {U}.)
As Hallowed Fountain enters, you may pay 2 life. If you don't, it enters tapped.

Sol Ring

Battlefield Forge

{T}: Add {C}.
{T}: Add {R} or {W}. Battlefield Forge deals 1 damage to you.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Sea of Clouds

Sea of Clouds enters tapped unless you have two or more opponents.
{T}: Add {W} or {U}.

Talisman of Progress

{T}: Add {C}.
{T}: Add {W} or {U}. Talisman of Progress deals 1 damage to you.

Island

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Rootborn Defenses

Populate. Creatures you control gain indestructible until end of turn. (To populate, create a token that's a copy of a creature token you control.)

Sulfur Falls

Sulfur Falls enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Mystic Monastery

Mystic Monastery enters tapped.
{T}: Add {U}, {R}, or {W}.

Command Tower

Perilous Landscape

{T}: Add {C}.
{T}, Sacrifice Perilous Landscape: Search your library for a basic Island, Mountain, or Plains card, put it onto the battlefield tapped, then shuffle.
Cycling {U}{R}{W} ({U}{R}{W}, Discard this card: Draw a card.)

Zinnia, Valley's Voice

Flying
Zinnia, Valley's Voice gets +X/+0, where X is the number of other creatures you control with base power 1.
Creature spells you cast have offspring {2}. (You may pay an additional {2} as you cast a creature spell. If you do, when that creature enters, create a 1/1 token copy of it.)

Plains

Raugrin Triome

({T}: Add {U}, {R}, or {W}.)
Raugrin Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Talisman of Creativity

{T}: Add {C}.
{T}: Add {U} or {R}. Talisman of Creativity deals 1 damage to you.

Boros Signet

Spectator Seating

Spectator Seating enters tapped unless you have two or more opponents.
{T}: Add {R} or {W}.

Mountain

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Clifftop Retreat

Clifftop Retreat enters tapped unless you control a Mountain or a Plains.
{T}: Add {R} or {W}.

Exotic Orchard

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

Shivan Reef

{T}: Add {C}.
{T}: Add {U} or {R}. Shivan Reef deals 1 damage to you.

Sacred Foundry

({T}: Add {R} or {W}.)
As Sacred Foundry enters, you may pay 2 life. If you don't, it enters tapped.

Steam Vents

({T}: Add {U} or {R}.)
As Steam Vents enters, you may pay 2 life. If you don't, it enters tapped.

Determined Iteration

At the beginning of combat on your turn, populate. The token created this way gains haste. Sacrifice it at the beginning of the next end step. (To populate, create a token that's a copy of a creature token you control.)

Talisman of Conviction

{T}: Add {C}.
{T}: Add {R} or {W}. Talisman of Conviction deals 1 damage to you.

Azorius Signet

Prairie Stream

({T}: Add {W} or {U}.)
Prairie Stream enters tapped unless you control two or more basic lands.