Sea of Clouds

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

Sword of Fire and Ice

Equipped creature gets +2/+2 and has protection from red and from blue.
Whenever equipped creature deals combat damage to a player, Sword of Fire and Ice deals 2 damage to any target and you draw a card.
Equip {2}

Phantasmal Image

You may have Phantasmal Image enter as a copy of any creature on the battlefield, except it's an Illusion in addition to its other types and it has "When this creature becomes the target of a spell or ability, sacrifice it."

Azorius Signet

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Generous Gift

Destroy target permanent. Its controller creates a 3/3 green Elephant creature token.

Negate

Geist of Saint Traft

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
Whenever Geist of Saint Traft attacks, create a 4/4 white Angel creature token with flying that's tapped and attacking. Exile that token at end of combat.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Kira, Great Glass-Spinner

Flying
Creatures you control have "Whenever this creature becomes the target of a spell or ability for the first time each turn, counter that spell or ability."

Supreme Phantom

Flying
Other Spirits you control get +1/+1.

Adaptive Automaton

As Adaptive Automaton enters, choose a creature type.
Adaptive Automaton is the chosen type in addition to its other types.
Other creatures you control of the chosen type get +1/+1.

Plains

Flooded Strand

{T}, Pay 1 life, Sacrifice Flooded Strand: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Rattlechains

Flash
Flying
When Rattlechains enters, target Spirit gains hexproof until end of turn.
You may cast Spirit spells as though they had flash.

Hallowed Fountain

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

Glacial Fortress

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

Absorb

Sundial of the Infinite

{1}, {T}: End the turn. Activate only during your turn. (Exile all spells and abilities from the stack. Discard down to your maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.)

Drogskol Captain

Flying
Other Spirit creatures you control get +1/+1 and have hexproof. (They can't be the targets of spells or abilities your opponents control.)

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Swords to Plowshares

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

Tundra

Skyclave Apparition

When Skyclave Apparition enters, exile up to one target nonland, nontoken permanent you don't control with mana value 4 or less.
When Skyclave Apparition leaves the battlefield, the exiled card's owner creates an X/X blue Illusion creature token, where X is the mana value of the exiled card.

Strict Proctor

Flying
Whenever a permanent entering causes a triggered ability to trigger, counter that ability unless its controller pays {2}.

Steel of the Godhead

Enchant creature
As long as enchanted creature is white, it gets +1/+1 and has lifelink. (Damage dealt by the creature also causes its controller to gain that much life.)
As long as enchanted creature is blue, it gets +1/+1 and can't be blocked.

Command Tower

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

Favorable Winds

Creatures you control with flying get +1/+1.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Island

Spectral Shepherd

Flying
{1}{U}: Return target Spirit you control to its owner's hand.

Invocation of Saint Traft

Enchant creature
Enchanted creature has "Whenever this creature attacks, create a 4/4 white Angel creature token with flying that's tapped and attacking. Exile that token at end of combat."

Hanged Executioner

Flying
When Hanged Executioner enters, create a 1/1 white Spirit creature token with flying.
{3}{W}, Exile Hanged Executioner: Exile target creature.

Tranquil Cove

Tranquil Cove enters tapped.
When Tranquil Cove enters, you gain 1 life.
{T}: Add {W} or {U}.

Arcane Signet

Empyrean Eagle

Flying
Other creatures you control with flying get +1/+1.

Prairie Stream

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

Oblivion Ring

When Oblivion Ring enters, exile another target nonland permanent.
When Oblivion Ring leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Disenchant

Aqueous Form

Enchant creature
Enchanted creature can't be blocked.
Whenever enchanted creature attacks, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Mother of Runes

{T}: Target creature you control gains protection from the color of your choice until end of turn.