Gateway Plaza

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

Unknown Shores

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Counter target spell unless its controller pays {2}.

Flying, vigilance
Spells your opponents cast that target Sphinx of New Prahv cost {2} more to cast.

{W}, {T}: You gain 2 life.
{U}, {T}: Draw a card, then discard a card.

Vigilance
Azorius Knight-Arbiter can't be blocked.

Whenever Nine-Tail White Fox deals combat damage to a player, draw a card.

Flash
When Omen of the Sea enters, scry 2, then draw a card.
{2}{U}, Sacrifice Omen of the Sea: Scry 2.

Return target creature or enchantment an opponent controls to its owner's hand.

{1}, Sacrifice Traveler's Amulet: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.

This spell costs {1} less to cast if you control a creature with flying.
Draw two cards.

Azorius Guildgate enters tapped.
{T}: Add {W} or {U}.

{T}: Add {W} or {U}.
{W/U}{W/U}{W/U}{W/U}, {T}, Sacrifice Azorius Locket: Draw two cards.

Whenever another creature you control enters, you gain 1 life.

Whenever Haazda Marshal and at least two other creatures attack, create a 1/1 white Soldier creature token with lifelink.

Create a 2/2 white Knight creature token with vigilance. (Then exile this card. You may cast the creature later from exile.)

Enchant creature or planeswalker
Enchanted permanent can't attack or block, and its activated abilities can't be activated.

Whenever you gain life, put a +1/+1 counter on Celestial Unicorn.