Mana Leak

Counter target spell unless its controller pays {3}.

Witching Well

When Witching Well enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)
{3}{U}, Sacrifice Witching Well: Draw two cards.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Faerie Seer

Flying
When Faerie Seer enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Transcendent Envoy

Flying
Aura spells you cast cost {1} less to cast.

Heliod's Pilgrim

When Heliod's Pilgrim enters, you may search your library for an Aura card, reveal it, put it into your hand, then shuffle.

Ephemerate

Exile target creature you control, then return it to the battlefield under its owner's control.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Holy Light

Nonwhite creatures get -1/-1 until end of turn.

Serrated Arrows

Serrated Arrows enters with three arrowhead counters on it.
At the beginning of your upkeep, if there are no arrowhead counters on Serrated Arrows, sacrifice it.
{T}, Remove an arrowhead counter from Serrated Arrows: Put a -1/-1 counter on target creature.

Circle of Protection: Red

{1}: The next time a red source of your choice would deal damage to you this turn, prevent that damage.

Omen of the Sea

Flash (You may cast this spell any time you could cast an instant.)
When Omen of the Sea enters, scry 2, then draw a card.
{2}{U}, Sacrifice Omen of the Sea: Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Echoing Truth

Return target nonland permanent and all other permanents with the same name as that permanent to their owners' hands.

Sunscape Familiar

Defender (This creature can't attack.)
Green spells and blue spells you cast cost {1} less to cast.

Palace Sentinels

When Palace Sentinels enters, you become the monarch.

Teferi's Time Twist

Exile target permanent you control. Return that card to the battlefield under its owner's control at the beginning of the next end step. If it enters as a creature, it enters with an additional +1/+1 counter on it.

Faith's Fetters

Enchant permanent
When Faith's Fetters enters, you gain 4 life.
Enchanted permanent can't attack or block, and its activated abilities can't be activated unless they're mana abilities.

Preordain

Scry 2, then draw a card. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Journey to Nowhere

When Journey to Nowhere enters, exile target creature.
When Journey to Nowhere leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Snow-Covered Island

Mulldrifter

Flying
When Mulldrifter enters, draw two cards.
Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Kor Skyfisher

Flying
When Kor Skyfisher enters, return a permanent you control to its owner's hand.

Dispel

Starnheim Courser

Flying
Artifact and enchantment spells you cast cost {1} less to cast.

Dream Stalker

When Dream Stalker enters, return a permanent you control to its owner's hand.

Reality Acid

Enchant permanent
Vanishing 3 (This Aura enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When Reality Acid leaves the battlefield, enchanted permanent's controller sacrifices it.

Snow-Covered Plains

Radiant Fountain

When Radiant Fountain enters, you gain 2 life.
{T}: Add {C}.

Flicker of Fate

Exile target creature or enchantment, then return it to the battlefield under its owner's control.

Azorius Chancery

Azorius Chancery enters tapped.
When Azorius Chancery enters, return a land you control to its owner's hand.
{T}: Add {W}{U}.

Remove Enchantments

Return to your hand all enchantments you both own and control, all Auras you own attached to permanents you control, and all Auras you own attached to attacking creatures your opponents control. Then destroy all other enchantments you control, all other Auras attached to permanents you control, and all other Auras attached to attacking creatures your opponents control.

Ash Barrens

{T}: Add {C}.
Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)