Ugin, the Ineffable

Colorless spells you cast cost {2} less to cast.
+1: Exile the top card of your library face down and look at it. Create a 2/2 colorless Spirit creature token. When that token leaves the battlefield, put the exiled card into your hand.
−3: Destroy target permanent that's one or more colors.

Fiend Hunter

When Fiend Hunter enters, you may exile another target creature.
When Fiend Hunter leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Boreas Charger

Flying
When Boreas Charger leaves the battlefield, choose an opponent who controls more lands than you. Search your library for a number of Plains cards equal to the difference, reveal those cards, put one of them onto the battlefield tapped and the rest into your hand, then shuffle.

Binding Mummy

Whenever another Zombie you control enters, you may tap target artifact or creature.

Scapegoat

As an additional cost to cast this spell, sacrifice a creature.
Return any number of target creatures you control to their owner's hand.

Prismatic Lens

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

Mentor of the Meek

Whenever another creature you control with power 2 or less enters, you may pay {1}. If you do, draw a card.

Dust Elemental

Flash (You may cast this spell any time you could cast an instant.)
Flying; fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
When Dust Elemental enters, return three creatures you control to their owner's hand.

Ondu Skyruins

Ondu Skyruins enters tapped.
{T}: Add {W}.

Ondu Inversion

Ondu Inversion // Ondu Skyruins

Rogue's Passage

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

Plains

New Benalia

New Benalia enters tapped.
When New Benalia enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {W}.

Odric, Lunarch Marshal

At the beginning of each combat, creatures you control gain first strike until end of turn if a creature you control has first strike. The same is true for flying, deathtouch, double strike, haste, hexproof, indestructible, lifelink, menace, reach, skulk, trample, and vigilance.

Endless Atlas

{2}, {T}: Draw a card. Activate only if you control three or more lands with the same name.

Leonin Relic-Warder

When Leonin Relic-Warder enters, you may exile target artifact or enchantment.
When Leonin Relic-Warder leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Forsake the Worldly

Exile target artifact or enchantment.
Cycling {2} ({2}, Discard this card: Draw a card.)

Victory's Herald

Flying
Whenever Victory's Herald attacks, attacking creatures gain flying and lifelink until end of turn.

Cryptic Caves

{T}: Add {C}.
{1}, {T}, Sacrifice this land: Draw a card. Activate only if you control five or more lands.

Chop Down

Destroy target creature with power 4 or greater. (Then exile this card. You may cast the creature later from exile.)

Giant Killer

Giant Killer // Chop Down

Secluded Steppe

Secluded Steppe enters tapped.
{T}: Add {W}.
Cycling {W} ({W}, Discard this card: Draw a card.)

Valor in Akros

Whenever a creature you control enters, creatures you control get +1/+1 until end of turn.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Fanatical Devotion

Sacrifice a creature: Regenerate target creature.

Arch of Orazca

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
{T}: Add {C}.
{5}, {T}: Draw a card. Activate only if you have the city's blessing.

Kor Skyfisher

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

Sejiri Glacier

Sejiri Glacier enters tapped.
{T}: Add {W}.

Sejiri Shelter

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

Sejiri Shelter // Sejiri Glacier

Sol Ring

Unbreakable Formation

Creatures you control gain indestructible until end of turn.
Addendum — If you cast this spell during your main phase, put a +1/+1 counter on each of those creatures and they gain vigilance until end of turn.

Selfless Savior

Sacrifice Selfless Savior: Another target creature you control gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Mardu Woe-Reaper

Whenever Mardu Woe-Reaper or another Warrior you control enters, you may exile target creature card from a graveyard. If you do, you gain 1 life.

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.)

Dreamstone Hedron

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

Stormfront Riders

Flying
When Stormfront Riders enters, return two creatures you control to their owner's hand.
Whenever Stormfront Riders or another creature is returned to your hand from the battlefield, create a 1/1 white Soldier creature token.

Oketra's Monument

White creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, create a 1/1 white Warrior creature token with vigilance.

Jeskai Barricade

Flash (You may cast this spell any time you could cast an instant.)
Defender
When Jeskai Barricade enters, you may return another target creature you control to its owner's hand.

Idol of Oblivion

{T}: Draw a card. Activate only if you created a token this turn.
{8}, {T}, Sacrifice Idol of Oblivion: Create a 10/10 colorless Eldrazi creature token.

Divine Reckoning

Each player chooses a creature they control. Destroy the rest.
Flashback {5}{W}{W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Skyclave Basilica

Skyclave Basilica enters tapped.
{T}: Add {W}.

Skyclave Cleric

When Skyclave Cleric enters, you gain 2 life.

Skyclave Cleric // Skyclave Basilica

Generous Gift

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

Usher to Safety

Return target permanent you control to its owner's hand. (Then exile this card. You may cast the creature later from exile.)

Shepherd of the Flock

Shepherd of the Flock // Usher to Safety

Hedron Archive

{T}: Add {C}{C}.
{2}, {T}, Sacrifice this artifact: Draw two cards.

Heraldic Banner

As this artifact enters, choose a color.
Creatures you control of the chosen color get +1/+0.
{T}: Add one mana of the chosen color.

Thraben Inspector

When Thraben Inspector enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

God-Eternal Oketra

Double strike
Whenever you cast a creature spell, create a 4/4 black Zombie Warrior creature token with vigilance.
When God-Eternal Oketra dies or is put into exile from the battlefield, you may put it into its owner's library third from the top.

Desert of the True

Desert of the True enters tapped.
{T}: Add {W}.
Cycling {1}{W} ({1}{W}, Discard this card: Draw a card.)

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Bygone Bishop

Flying
Whenever you cast a creature spell with mana value 3 or less, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

End Hostilities

Destroy all creatures and all permanents attached to creatures.

Whitemane Lion

Flash
When Whitemane Lion enters, return a creature you control to its owner's hand.

Tome of Legends

Tome of Legends enters with a page counter on it.
Whenever your commander enters or attacks, put a page counter on Tome of Legends.
{1}, {T}, Remove a page counter from Tome of Legends: Draw a card.

Wall of Omens

Defender
When Wall of Omens enters, draw a card.

War Priest of Thune

When War Priest of Thune enters, you may destroy target enchantment.

Makindi Mesas

Makindi Mesas enters tapped.
{T}: Add {W}.

Makindi Stampede

Creatures you control get +2/+2 until end of turn.

Makindi Stampede // Makindi Mesas

Pilgrim's Eye

Flying
When Pilgrim's Eye enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Marshal's Anthem

Multikicker {1}{W} (You may pay an additional {1}{W} any number of times as you cast this spell.)
Creatures you control get +1/+1.
When Marshal's Anthem enters, return up to X target creature cards from your graveyard to the battlefield, where X is the number of times Marshal's Anthem was kicked.

Bonders' Enclave

{T}: Add {C}.
{3}, {T}: Draw a card. Activate only if you control a creature with power 4 or greater.

Cast Out

Flash
When Cast Out enters, exile target nonland permanent an opponent controls until Cast Out leaves the battlefield.
Cycling {W} ({W}, Discard this card: Draw a card.)

Condemn

Put target attacking creature on the bottom of its owner's library. Its controller gains life equal to its toughness.

Kabira Plateau

Kabira Plateau enters tapped.
{T}: Add {W}.

Kabira Takedown

Kabira Takedown deals damage equal to the number of creatures you control to target creature or planeswalker.

Kabira Takedown // Kabira Plateau

Stonecloaker

Flash
Flying
When Stonecloaker enters, return a creature you control to its owner's hand.
When Stonecloaker enters, exile target card from a graveyard.

Unconventional Tactics

Target creature gets +3/+3 and gains flying until end of turn.
Whenever a Zombie you control enters, you may pay {W}. If you do, return Unconventional Tactics from your graveyard to your hand.

Idyllic Grange

({T}: Add {W}.)
Idyllic Grange enters tapped unless you control three or more other Plains.
When Idyllic Grange enters untapped, put a +1/+1 counter on target creature you control.

Guardian Idol

Guardian Idol enters tapped.
{T}: Add {C}.
{2}: Guardian Idol becomes a 2/2 Golem artifact creature until end of turn.

True Conviction

Creatures you control have double strike and lifelink.

Drifting Meadow

Drifting Meadow enters tapped.
{T}: Add {W}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Skyscanner

Flying
When Skyscanner enters, draw a card.

Dictate of Heliod

Obsidian Battle-Axe

Equipped creature gets +2/+1 and has haste.
Whenever a Warrior creature enters, you may attach Obsidian Battle-Axe to it.
Equip {3}

Emancipation Angel

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

Parhelion II

Flying, first strike, vigilance
Whenever Parhelion II attacks, create two 4/4 white Angel creature tokens with flying and vigilance that are attacking.
Crew 4 (Tap any number of creatures you control with total power 4 or more: This Vehicle becomes an artifact creature until end of turn.)

Swords to Plowshares

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

Kor Cartographer

When Kor Cartographer enters, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle.

Cast Off

Destroy all non-Giant creatures. (Then exile this card. You may cast the creature later from exile.)