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.

The Spear of Leonidas

Whenever equipped creature attacks, choose one —
• Bull Rush — It gains double strike until end of turn.
• Summon — Create Phobos, a legendary 3/2 red Horse creature token.
• Revelation — Discard two cards, then draw two cards.
Equip {2}

Éowyn, Fearless Knight

Haste
When Éowyn, Fearless Knight enters, exile target creature an opponent controls with greater power. Legendary creatures you control gain protection from each of that creature's colors until end of turn.

Vanquisher's Banner

As Vanquisher's Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Armored Warhorse

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.

Archivist of Oghma

Flash
Whenever an opponent searches their library, you gain 1 life and draw a card.

Palace Jailer

When Palace Jailer enters, you become the monarch.
When Palace Jailer enters, exile target creature an opponent controls until an opponent becomes the monarch.

Horn of the Mark

Whenever two or more creatures you control attack a player, look at the top five cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Mirror Entity

Changeling (This card is every creature type.)
{X}: Until end of turn, creatures you control have base power and toughness X/X and gain all creature types.

Rally the Ranks

As Rally the Ranks enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.

Calamity, Galloping Inferno

Haste
Whenever Calamity, Galloping Inferno attacks while saddled, choose a nonlegendary creature that saddled it this turn and create a tapped and attacking token that's a copy of it. Sacrifice that token at the beginning of the next end step. Repeat this process once.
Saddle 1

Mind Stone

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

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.

Thundermare

Haste (This creature can attack and {T} as soon as it comes under your control.)
When Thundermare enters, tap all other creatures.

Arcane Signet

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

Helm of the Host

At the beginning of combat on your turn, create a token that's a copy of equipped creature, except the token isn't legendary. That token gains haste.
Equip {5}

Command Tower

Shadowfax, Lord of Horses

Horses you control have haste. (They can attack and {T} as soon as they come under your control.)
Whenever Shadowfax, Lord of Horses attacks, you may put a creature card with lesser power from your hand onto the battlefield tapped and attacking.

Nyxborn Unicorn

Bestow {3}{W} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached.)
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Enchanted creature gets +2/+2 and has mentor.

Generous Gift

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

Knight of the White Orchid

First strike
When Knight of the White Orchid 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.

Lightning Mare

This spell can't be countered.
Lightning Mare can't be blocked by blue creatures.
{1}{R}: Lightning Mare gets +1/+0 until end of turn.

Gold Myr

Bastion Protector

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

Crested Sunmare

Other Horses you control have indestructible.
At the beginning of each end step, if you gained life this turn, create a 5/5 white Horse creature token.

Alms Collector

Flash
If an opponent would draw two or more cards, instead you and that player each draw a card.

Smuggler's Share

At the beginning of each end step, draw a card for each opponent who drew two or more cards this turn, then create a Treasure token for each opponent who had two or more lands enter the battlefield under their control this turn.

Diamond Mare

As Diamond Mare enters, choose a color.
Whenever you cast a spell of the chosen color, you gain 1 life.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Swords to Plowshares

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

Boros Signet

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Bill the Pony

When Bill the Pony enters, create two Food tokens. (They're artifacts with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
Sacrifice a Food: Until end of turn, target creature you control assigns combat damage equal to its toughness rather than its power.

Flowering of the White Tree

Legendary creatures you control get +2/+1 and have ward {1}.
Nonlegendary creatures you control get +1/+1.

Plains

Commander's Sphere

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

Aerial Surveyor

Flying
Whenever Aerial Surveyor attacks, if defending player controls more lands than you, search your library for a basic Plains card, put it onto the battlefield tapped, then shuffle.
Crew 2

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.

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Blade Historian

Attacking creatures you control have double strike.

Loyal Unicorn

Vigilance
Lieutenant — At the beginning of combat on your turn, if you control your commander, prevent all combat damage that would be dealt to creatures you control this turn. Other creatures you control gain vigilance until end of turn.

Chrome Steed

Metalcraft — Chrome Steed gets +2/+2 as long as you control three or more artifacts.

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}

Reprieve

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

True Conviction

Creatures you control have double strike and lifelink.

Folk Hero

Commander creatures you own have "Whenever you cast a spell that shares a creature type with this creature, draw a card. This ability triggers only once each turn."

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Mountain

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.)

Balefire Liege

Other red creatures you control get +1/+1.
Other white creatures you control get +1/+1.
Whenever you cast a red spell, Balefire Liege deals 3 damage to target player or planeswalker.
Whenever you cast a white spell, you gain 3 life.

Shield Mare

Shield Mare can't be blocked by red creatures.
When Shield Mare enters or becomes the target of a spell or ability an opponent controls, you gain 3 life.

Radiant Destiny

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
As Radiant Destiny enters, choose a creature type.
Creatures you control of the chosen type get +1/+1. As long as you have the city's blessing, they also have vigilance.

Keleth, Sunmane Familiar

Whenever a commander you control attacks, put a +1/+1 counter on it.
Partner (You can have two commanders if both have partner.)