Akroma, Vision of Ixidor

Flying, first strike, vigilance, trample
At the beginning of each combat, until end of turn, each other creature you control gets +1/+1 if it has flying, +1/+1 if it has first strike, and so on for double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, protection, reach, trample, vigilance, and partner.
Partner

Gideon Blackblade

During your turn, Gideon Blackblade is a 4/4 Human Soldier creature with indestructible that's still a planeswalker.
Prevent all damage that would be dealt to Gideon Blackblade during your turn.
+1: Up to one other target creature you control gains your choice of vigilance, lifelink, or indestructible until end of turn.
−6: Exile target nonland permanent.

Cartographer's Hawk

Flying
When this creature deals combat damage to a player who controls more lands than you, return it to its owner's hand. If you do, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle.

Chivalric Alliance

Whenever you attack with two or more creatures, draw a card.
{2}, Discard a card: Create a 2/2 white and blue Knight creature token with vigilance.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Cast Off

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

Realm-Cloaked Giant

Realm-Cloaked Giant // Cast Off

Reprieve

Return target spell to its owner's hand.
Draw a card.

Claim Jumper

Vigilance
When this creature enters, if an opponent controls more lands than you, you may search your library for a Plains card and put it onto the battlefield tapped. Then if an opponent controls more lands than you, repeat this process once. If you search your library this way, shuffle.

Battlefield Raptor

Sejiri Glacier

Sejiri Shelter

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

Sejiri Shelter // Sejiri Glacier

Swords to Plowshares

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

Fey Steed

Whenever this creature attacks, another target attacking creature you control gains indestructible until end of turn.
Whenever a creature or planeswalker you control becomes the target of a spell or ability an opponent controls, you may draw a card.

Cut a Deal

Each opponent draws a card, then you draw a card for each opponent who drew a card this way.

Stoic Farmer

When this creature enters, search your library for a basic Plains card and reveal it. If an opponent controls more lands than you, put it onto the battlefield tapped. Otherwise, put it into your hand. Then shuffle.
Foretell {1}{W} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Windbrisk Heights

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
This land enters tapped.
{T}: Add {W}.
{W}, {T}: You may play the exiled card without paying its mana cost if you attacked with three or more creatures this turn.

Bastion Protector

Commander creatures you control get +2/+2 and have indestructible.

Mobilized District

{T}: Add {C}.
{4}: This land becomes a 3/3 Citizen creature with vigilance until end of turn. It's still a land. This ability costs {1} less to activate for each legendary creature and planeswalker you control.

Basilisk Collar

Equipped creature has deathtouch and lifelink. (Any amount of damage it deals to a creature is enough to destroy it. Damage dealt by this creature also causes you to gain that much life.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Hanged Executioner

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

Swooping Lookout

Brightblade Stoat

Angel of Invention

Flying, vigilance, lifelink
Fabricate 2 (When this creature enters, put two +1/+1 counters on it or create two 1/1 colorless Servo artifact creature tokens.)
Other creatures you control get +1/+1.

Mangara of Corondor

Kabira Plateau

Kabira Takedown

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

Kabira Takedown // Kabira Plateau

Lay Down Arms

Exile target creature with mana value less than or equal to the number of Plains you control. Its controller gains 3 life.

Winds of Abandon

Exile target creature you don't control. For each creature exiled this way, its controller searches their library for a basic land card. Those players put those cards onto the battlefield tapped, then shuffle.
Overload {4}{W}{W} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

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.

Haunted Cloak

Equipped creature has vigilance, trample, and haste.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Crystalline Giant

At the beginning of combat on your turn, choose a kind of counter at random that this creature doesn't have on it from among flying, first strike, deathtouch, hexproof, lifelink, menace, reach, trample, vigilance, and +1/+1. Put a counter of that kind on this creature.

Keeper of the Accord

At the beginning of each opponent's end step, if that player controls more creatures than you, create a 1/1 white Soldier creature token.
At the beginning of each opponent's end step, if that player controls more lands than you, you may search your library for a basic Plains card, put it onto the battlefield tapped, then shuffle.

Welcoming Vampire

Flying
Whenever one or more other creatures you control with power 2 or less enter, draw a card. This ability triggers only once each turn.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Pearl Medallion

White spells you cast cost {1} less to cast.

It That Rides as One

Lone Rider

First strike, lifelink
At the beginning of the end step, if you gained 3 or more life this turn, transform this creature.

Lone Rider // It That Rides as One

Gideon of the Trials

+1: Until your next turn, prevent all damage target permanent would deal.
0: Until end of turn, Gideon becomes a 4/4 Human Soldier creature with indestructible that's still a planeswalker. Prevent all damage that would be dealt to him this turn.
0: You get an emblem with "As long as you control a Gideon planeswalker, you can't lose the game and your opponents can't win the game."

Aerial Responder

Oketra the True

Double strike, indestructible
Oketra can't attack or block unless you control at least three other creatures.
{3}{W}: Create a 1/1 white Warrior creature token with vigilance.

Knight of the White Orchid

First strike
When this creature enters, if an opponent controls more lands than you, you may search your library for a Plains card, put it onto the battlefield, then shuffle.

Secret Rendezvous

You and target opponent each draw three cards.

Zetalpa, Primal Dawn

Flying, double strike, vigilance, trample, indestructible

Sol Ring

Sun Titan

Vigilance
Whenever this creature enters or attacks, you may return target permanent card with mana value 3 or less from your graveyard to the battlefield.

Generous Gift

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

Gorgon's Head

Equipped creature has deathtouch.
Equip {2}

Rumor Gatherer

Alliance — Whenever another creature you control enters, scry 1. If this is the second time this ability has resolved this turn, draw a card instead.

Firemane Commando

Flying
Whenever you attack with two or more creatures, draw a card.
Whenever another player attacks with two or more creatures, they draw a card if none of those creatures attacked you.

Terrain Generator

{T}: Add {C}.
{2}, {T}: You may put a basic land card from your hand onto the battlefield tapped.

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.

Heliod, God of the Sun

Indestructible
As long as your devotion to white is less than five, Heliod isn't a creature. (Each {W} in the mana costs of permanents you control counts toward your devotion to white.)
Other creatures you control have vigilance.
{2}{W}{W}: Create a 2/1 white Cleric enchantment creature token.

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.

Remorseful Cleric

Flying
Sacrifice this creature: Exile target player's graveyard.

Odric, Master Tactician

First strike (This creature deals combat damage before creatures without first strike.)
Whenever Odric and at least three other creatures attack, you choose which creatures block this combat and how those creatures block.

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.

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.

Defiler of Faith

Vigilance
As an additional cost to cast white permanent spells, you may pay 2 life. Those spells cost {W} less to cast if you paid life this way. This effect reduces only the amount of white mana you pay.
Whenever you cast a white permanent spell, create a 1/1 white Soldier creature token.

Minas Tirith

Minas Tirith enters tapped unless you control a legendary creature.
{T}: Add {W}.
{1}{W}, {T}: Draw a card. Activate only if you attacked with two or more creatures this turn.

Loyal Warhound

Vigilance
When this creature enters, if an opponent controls more lands than you, search your library for a basic Plains card, put it onto the battlefield tapped, then shuffle.

Makindi Mesas

Makindi Stampede

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

Makindi Stampede // Makindi Mesas

Armored Ascension

Enchant creature
Enchanted creature gets +1/+1 for each Plains you control and has flying.

Mangara, the Diplomat

Lifelink
Whenever an opponent attacks with creatures, if two or more of those creatures are attacking you and/or planeswalkers you control, draw a card.
Whenever an opponent casts their second spell each turn, draw a card.

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.

Lapse of Certainty

Counter target spell. If that spell is countered this way, put it on top of its owner's library instead of into that player's graveyard.

Cave of the Frost Dragon

If you control two or more other lands, this land enters tapped.
{T}: Add {W}.
{4}{W}: This land becomes a 3/4 white Dragon creature with flying until end of turn. It's still a land.

The Fair Basilica

This land enters tapped.
{T}: Add {W}.
{1}{W}, {T}, Sacrifice this land: Draw a card.

Recruiter of the Guard

When this creature enters, you may search your library for a creature card with toughness 2 or less, reveal it, put it into your hand, then shuffle.

Plains

Mass Calcify

Fencing Ace

Double strike (This creature deals both first-strike and regular combat damage.)

Myriad Landscape

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

Bounty Agent

Vigilance
{T}, Sacrifice this creature: Destroy target legendary permanent that's an artifact, creature, or enchantment.

Tocasia's Welcome

Whenever one or more creatures you control with mana value 3 or less enter, draw a card. This ability triggers only once each turn.

Healer's Hawk

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)