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}

Barbed Wire

At the beginning of each player's upkeep, Barbed Wire deals 1 damage to that player.
{2}: Prevent the next 1 damage that would be dealt by Barbed Wire this turn.

Ellyn Harbreeze, Busybody

{T}: Look at the top X cards of your library, where X is the number of tokens you created this turn. Put one of those cards into your hand and the rest on the bottom of your library in a random order.
Choose a Background (You can have a Background as a second commander.)

Genesis Chamber

Whenever a nontoken creature enters, if Genesis Chamber is untapped, that creature's controller creates a 1/1 colorless Myr artifact creature token.

Ankh of Mishra

Whenever a land enters, Ankh of Mishra deals 2 damage to that land's controller.

Thespian's Stage

{T}: Add {C}.
{2}, {T}: Thespian's Stage becomes a copy of target land, except it has this ability.

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Fire and Brimstone

Fire and Brimstone deals 4 damage to target player who attacked this turn and 4 damage to you.

Darien, King of Kjeldor

Whenever you're dealt damage, you may create that many 1/1 white Soldier creature tokens.

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.

Land Tax

At the beginning of your upkeep, if an opponent controls more lands than you, you may search your library for up to three basic land cards, reveal them, put them into your hand, then shuffle.

Boss's Chauffeur

Boss's Chauffeur enters with a number of +1/+1 counters on it equal to one plus the number of other creatures you control.
Alliance — Whenever another creature you control enters, put a +1/+1 counter on Boss's Chauffeur.
When Boss's Chauffeur dies, create a 1/1 green and white Citizen creature token for each +1/+1 counter on it.

Tarnished Citadel

{T}: Add {C}.
{T}: Add one mana of any color. Tarnished Citadel deals 3 damage to you.

Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Urza's Saga gains "{T}: Add {C}."
II — Urza's Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This creature gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

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.

Karoo

Karoo enters tapped.
When Karoo enters, sacrifice it unless you return an untapped Plains you control to its owner's hand.
{T}: Add {C}{W}.

Dingus Egg

Whenever a land is put into a graveyard from the battlefield, Dingus Egg deals 2 damage to that land's controller.

Ajani's Welcome

Whenever a creature you control enters, you gain 1 life.

Sword of Hearth and Home

Equipped creature gets +2/+2 and has protection from green and from white.
Whenever equipped creature deals combat damage to a player, exile up to one target creature you own, then search your library for a basic land card. Put both cards onto the battlefield under your control, then shuffle.
Equip {2}

Copper Tablet

At the beginning of each player's upkeep, Copper Tablet deals 1 damage to that player.

Blood of the Martyr

Until end of turn, if damage would be dealt to any creature, you may have that damage dealt to you instead.

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.

Farsight Mask

Whenever a source an opponent controls deals damage to you, if Farsight Mask is untapped, you may draw a card.

Coveted Jewel

When Coveted Jewel enters, draw three cards.
{T}: Add three mana of any one color.
Whenever one or more creatures an opponent controls attack you and aren't blocked, that player draws three cards and gains control of Coveted Jewel. Untap it.

Luminous Phantom

Flying
Whenever another creature you control leaves the battlefield, you gain 1 life.
If Luminous Phantom would be put into a graveyard from anywhere, exile it instead.

Lunarch Veteran

Whenever another creature you control enters, you gain 1 life.
Disturb {1}{W} (You may cast this card from your graveyard transformed for its disturb cost.)

Lunarch Veteran // Luminous Phantom

Suture Priest

Whenever another creature you control enters, you may gain 1 life.
Whenever a creature an opponent controls enters, you may have that player lose 1 life.

Jinxed Idol

At the beginning of your upkeep, Jinxed Idol deals 2 damage to you.
Sacrifice a creature: Target opponent gains control of Jinxed Idol.

Vesuva

You may have Vesuva enter tapped as a copy of any land on the battlefield.

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Cloudstone Curio

Whenever a nonartifact permanent you control enters, you may return another permanent you control that shares a permanent type with it to its owner's hand.

Bonders' Enclave

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

Archon of Coronation

Flying
When Archon of Coronation enters, you become the monarch.
As long as you're the monarch, damage doesn't cause you to lose life. (When a creature deals combat damage to you, its controller still becomes the monarch.)

Auriok Champion

Protection from black and from red
Whenever another creature enters, you may gain 1 life.

Icatian Moneychanger

Icatian Moneychanger enters with three credit counters on it.
When Icatian Moneychanger enters, it deals 3 damage to you.
At the beginning of your upkeep, put a credit counter on Icatian Moneychanger.
Sacrifice Icatian Moneychanger: You gain 1 life for each credit counter on Icatian Moneychanger. Activate only during your upkeep.

Deep Gnome Terramancer

Flash
Mold Earth — Whenever one or more lands enter under an opponent's control without being played, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle. Do this only once each turn.

Field Marshal

Other Soldier creatures get +1/+1 and have first strike. (They deal combat damage before creatures without first strike.)

Impassioned Orator

Whenever another creature you control enters, you gain 1 life.

Lotus Field

Hexproof
Lotus Field enters tapped.
When Lotus Field enters, sacrifice two lands.
{T}: Add three mana of any one color.

Inner Sanctum

Cumulative upkeep—Pay 2 life. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Prevent all damage that would be dealt to creatures you control.

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}

Cathars' Crusade

Whenever a creature you control enters, put a +1/+1 counter on each creature you control.

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.

Hunted Lammasu

Flying
When Hunted Lammasu enters, target opponent creates a 4/4 black Horror creature token.

Emeria, the Sky Ruin

Emeria, the Sky Ruin enters tapped.
At the beginning of your upkeep, if you control seven or more Plains, you may return target creature card from your graveyard to the battlefield.
{T}: Add {W}.

Dingus Staff

Whenever a creature dies, Dingus Staff deals 2 damage to that creature's controller.

Court of Grace

When Court of Grace enters, you become the monarch.
At the beginning of your upkeep, create a 1/1 white Spirit creature token with flying. If you're the monarch, create a 4/4 white Angel creature token with flying instead.

Lost Vale

(Transforms from Dowsing Dagger.)
{T}: Add three mana of any one color.

Dowsing Dagger

When Dowsing Dagger enters, target opponent creates two 0/2 green Plant creature tokens with defender.
Equipped creature gets +2/+1.
Whenever equipped creature deals combat damage to a player, you may transform Dowsing Dagger.
Equip {2}

Dowsing Dagger // Lost Vale

Ancient Tomb

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Magnetic Mine

Whenever another artifact is put into a graveyard from the battlefield, Magnetic Mine deals 2 damage to that artifact's controller.

Bennie Bracks, Zoologist

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
At the beginning of each end step, if you created a token this turn, draw a card.

Goblin Lyre

Sacrifice Goblin Lyre: Flip a coin. If you win the flip, Goblin Lyre deals damage to target opponent or planeswalker equal to the number of creatures you control. If you lose the flip, Goblin Lyre deals damage to you equal to the number of creatures that opponent or that planeswalker's controller controls.

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.
{T}: Add {C}{C}.

Catapult Master

Tap five untapped Soldiers you control: Exile target creature.

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.)
Windbrisk Heights 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.

Tyrite Sanctum

{T}: Add {C}.
{2}, {T}: Target legendary creature becomes a God in addition to its other types. Put a +1/+1 counter on it.
{4}, {T}, Sacrifice Tyrite Sanctum: Put an indestructible counter on target God.

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.

Archangel of Thune

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
Whenever you gain life, put a +1/+1 counter on each creature you control.

Alms Collector

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

Divine Visitation

If one or more creature tokens would be created under your control, that many 4/4 white Angel creature tokens with flying and vigilance are created instead.

Soul Warden

Whenever another creature enters, you gain 1 life.

Kjeldoran Outpost

If Kjeldoran Outpost would enter, sacrifice a Plains instead. If you do, put Kjeldoran Outpost onto the battlefield. If you don't, put it into its owner's graveyard.
{T}: Add {W}.
{1}{W}, {T}: Create a 1/1 white Soldier creature token.

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Psychogenic Probe

Whenever a spell or ability causes a player to shuffle their library, Psychogenic Probe deals 2 damage to that player.

Loyal Warhound

Vigilance
When Loyal Warhound 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.

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.

Castle Ardenvale

Castle Ardenvale enters tapped unless you control a Plains.
{T}: Add {W}.
{2}{W}{W}, {T}: Create a 1/1 white Human creature token.

Acorn Catapult

{1}, {T}: Acorn Catapult deals 1 damage to any target. That permanent's controller or that player creates a 1/1 green Squirrel creature token.

Cleansing Meditation

Destroy all enchantments.
Threshold — If seven or more cards are in your graveyard, instead destroy all enchantments, then return all cards in your graveyard destroyed this way to the battlefield.

Daxos, Blessed by the Sun

Daxos's toughness is equal to your devotion to white. (Each {W} in the mana costs of permanents you control counts toward your devotion to white.)
Whenever another creature you control enters or dies, you gain 1 life.

Divine Sacrament

White creatures get +1/+1.
Threshold — White creatures get an additional +1/+1 as long as seven or more cards are in your graveyard.

Mana Vault

Mana Vault doesn't untap during your untap step.
At the beginning of your upkeep, you may pay {4}. If you do, untap Mana Vault.
At the beginning of your draw step, if Mana Vault is tapped, it deals 1 damage to you.
{T}: Add {C}{C}{C}.

Battle Angels of Tyr

Flying, myriad
Whenever Battle Angels of Tyr deals combat damage to a player, draw a card if that player has more cards in hand than each other player. Then you create a Treasure token if that player controls more lands than each other player. Then you gain 3 life if that player has more life than each other player.

Nomad Stadium

{T}: Add {W}. Nomad Stadium deals 1 damage to you.
Threshold — {W}, {T}, Sacrifice Nomad Stadium: You gain 4 life. Activate only if seven or more cards are in your graveyard.

Karma

At the beginning of each player's upkeep, Karma deals damage to that player equal to the number of Swamps they control.

Paladin of Atonement

At the beginning of each upkeep, if you lost life last turn, put a +1/+1 counter on Paladin of Atonement.
When Paladin of Atonement dies, you gain life equal to its toughness.

Cold Snap

Cumulative upkeep {2} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
At the beginning of each player's upkeep, Cold Snap deals damage to that player equal to the number of snow lands they control.

Sword of Feast and Famine

Equipped creature gets +2/+2 and has protection from black and from green.
Whenever equipped creature deals combat damage to a player, that player discards a card and you untap all lands you control.
Equip {2}

Emergence Zone

{T}: Add {C}.
{1}, {T}, Sacrifice Emergence Zone: You may cast spells this turn as though they had flash.

Throne of the High City

{T}: Add {C}.
{4}, {T}, Sacrifice Throne of the High City: You become the monarch.

Weathered Wayfarer

{W}, {T}: Search your library for a land card, reveal it, put it into your hand, then shuffle. Activate only if an opponent controls more lands than you.

City of Brass

Whenever City of Brass becomes tapped, it deals 1 damage to you.
{T}: Add one mana of any color.

Serra Ascendant

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
As long as you have 30 or more life, Serra Ascendant gets +5/+5 and has flying.

Mana Confluence

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

Iron Mastiff

Whenever Iron Mastiff attacks, roll a d20 for each player being attacked and ignore all but the highest roll.
1—9 | Iron Mastiff deals damage equal to its power to you.
10—19 | Iron Mastiff deals damage equal to its power to defending player.
20 | Iron Mastiff deals damage equal to its power to each opponent.

Eiganjo, Seat of the Empire

{T}: Add {W}.
Channel — {2}{W}, Discard Eiganjo, Seat of the Empire: It deals 4 damage to target attacking or blocking creature. This ability costs {1} less to activate for each legendary creature you control.

Command Beacon

{T}: Add {C}.
{T}, Sacrifice Command Beacon: Put your commander into your hand from the command zone.

First Response

At the beginning of each upkeep, if you lost life last turn, create a 1/1 white Soldier creature token.