Have

Slayers' Stronghold

{T}: Add {C}.
{R}{W}, {T}: Target creature gets +2/+0 and gains vigilance and haste until end of turn.

Karlach, Fury of Avernus

Whenever you attack, if it's the first combat phase of the turn, untap all attacking creatures. They gain first strike until end of turn. After this phase, there is an additional combat phase.
Choose a Background (You can have a Background as a second commander.)

Hammers of Moradin

Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Whenever Hammers of Moradin attacks, for each opponent, tap up to one target creature that player controls.

Vanquish the Horde

This spell costs {1} less to cast for each creature on the battlefield.
Destroy all creatures.

Vault of the Archangel

{T}: Add {C}.
{2}{W}{B}, {T}: Creatures you control gain deathtouch and lifelink until end of turn.

Rabbit Battery

Haste
Equipped creature gets +1/+1 and has haste.
Reconfigure {R} ({R}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Fury of the Horde

You may exile two red cards from your hand rather than pay this spell's mana cost.
Untap all creatures that attacked this turn. After this main phase, there is an additional combat phase followed by an additional main phase.

Don't Have

Aggravated Assault

{3}{R}{R}: Untap all creatures you control. After this main phase, there is an additional combat phase followed by an additional main phase. Activate only as a sorcery.

Getting

Exotic Orchard

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

Thrill of Possibility

As an additional cost to cast this spell, discard a card.
Draw two cards.

Talisman of Hierarchy

{T}: Add {C}.
{T}: Add {W} or {B}. Talisman of Hierarchy deals 1 damage to you.

Sweeping Cleave

Target creature you control gains double strike until end of turn. (Then exile this card. You may cast the artifact later from exile.)

Two-Handed Axe

Whenever equipped creature attacks, double its power until end of turn.
Equip {1}{R}

Two-Handed Axe // Sweeping Cleave

Tymna the Weaver

Lifelink
At the beginning of each of your postcombat main phases, you may pay X life, where X is the number of opponents that were dealt combat damage this turn. If you do, draw X cards.
Partner (You can have two commanders if both have partner.)

Fracture

Destroy target artifact, enchantment, or planeswalker.

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.

Talisman of Indulgence

{T}: Add {C}.
{T}: Add {B} or {R}. Talisman of Indulgence deals 1 damage to you.

Caves of Koilos

{T}: Add {C}.
{T}: Add {W} or {B}. Caves of Koilos deals 1 damage to you.

Utter End

Port Razer

Whenever Port Razer deals combat damage to a player, untap each creature you control. After this phase, there is an additional combat phase.
Port Razer can't attack a player it has already attacked this turn.

Curse of Opulence

Enchant player
Whenever enchanted player is attacked, create a Gold token. Each opponent attacking that player does the same. (A Gold token is an artifact with "Sacrifice this artifact: Add one mana of any color.")

Arid Mesa

{T}, Pay 1 life, Sacrifice Arid Mesa: Search your library for a Mountain or Plains card, put it onto the battlefield, then shuffle.

Sign in Blood

Target player draws two cards and loses 2 life.

Trepanation Blade

Whenever equipped creature attacks, defending player reveals cards from the top of their library until they reveal a land card. The creature gets +1/+0 until end of turn for each card revealed this way. That player puts the revealed cards into their graveyard.
Equip {2}

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Rogue's Passage

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

Battlefield Forge

{T}: Add {C}.
{T}: Add {R} or {W}. Battlefield Forge deals 1 damage to you.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Moraug, Fury of Akoum

Each creature you control gets +1/+0 for each time it has attacked this turn.
Landfall — Whenever a land you control enters, if it's your main phase, there's an additional combat phase after this phase. At the beginning of that combat, untap all creatures you control.

Command Tower

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

Campaign of Vengeance

Whenever a creature you control attacks, defending player loses 1 life and you gain 1 life.

Talisman of Conviction

{T}: Add {C}.
{T}: Add {R} or {W}. Talisman of Conviction deals 1 damage to you.

Tori D'Avenant, Fury Rider

Vigilance, trample
Whenever Tori D'Avenant, Fury Rider attacks, all other attacking creatures you control get +1/+1 until end of turn. Other red attacking creatures you control gain trample until end of turn. Untap each other white attacking creature you control.

Sol Ring

Raiyuu, Storm's Edge

First strike
Whenever a Samurai or Warrior you control attacks alone, untap it. If it's the first combat phase of the turn, there is an additional combat phase after this phase.

Godo, Bandit Warlord

When Godo, Bandit Warlord enters, you may search your library for an Equipment card, put it onto the battlefield, then shuffle.
Whenever Godo attacks for the first time each turn, untap it and all Samurai you control. After this phase, there is an additional combat phase.

Blade of Selves

Equipped creature has myriad. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Equip {4}

Sulfurous Springs

{T}: Add {C}.
{T}: Add {B} or {R}. Sulfurous Springs deals 1 damage to you.

Orzhov Signet

Relentless Assault

Untap all creatures that attacked this turn. After this main phase, there is an additional combat phase followed by an additional main phase.

Resurgence

Creatures you control gain first strike and vigilance until end of turn. After this main phase, there is an additional combat phase followed by an additional main phase.

Response

Response deals 5 damage to target attacking or blocking creature.

Response // Resurgence

Vault of Champions

Vault of Champions enters tapped unless you have two or more opponents.
{T}: Add {W} or {B}.

Mind Stone

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

Rakdos Signet

Shiny Impetus

Enchant creature
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Arcane Signet

Duelist's Heritage

Whenever one or more creatures attack, you may have target attacking creature gain double strike until end of turn.

Phyrexian Dragon Engine

Double strike
When Phyrexian Dragon Engine enters from your graveyard, you may discard your hand. If you do, draw three cards.
Unearth {3}{R}{R}
(Melds with Mishra, Claimed by Gix.)

Swamp

Night's Whisper

Brutal Hordechief

Whenever a creature you control attacks, defending player loses 1 life and you gain 1 life.
{3}{R/W}{R/W}: Creatures your opponents control block this turn if able, and you choose how those creatures block.

Combat Celebrant

If Combat Celebrant hasn't been exerted this turn, you may exert it as it attacks. When you do, untap all other creatures you control and after this phase, there is an additional combat phase. (An exerted creature won't untap during your next untap step.)

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}

Krenko, Tin Street Kingpin

Whenever Krenko, Tin Street Kingpin attacks, put a +1/+1 counter on it, then create a number of 1/1 red Goblin creature tokens equal to Krenko's power.

Godless Shrine

({T}: Add {W} or {B}.)
As Godless Shrine enters, you may pay 2 life. If you don't, it enters tapped.

Boros Charm

Choose one —
• Boros Charm deals 4 damage to target player or planeswalker.
• Permanents you control gain indestructible until end of turn.
• Target creature gains double strike until end of turn.

Reinforced Ronin

Haste
At the beginning of your end step, return Reinforced Ronin to its owner's hand.
Channel — {1}{R}, Discard Reinforced Ronin: Draw a card.

Blood Crypt

({T}: Add {B} or {R}.)
As Blood Crypt enters, you may pay 2 life. If you don't, it enters tapped.

Commissar Severina Raine

Leading from the Front — Whenever Commissar Severina Raine attacks, each opponent loses X life, where X is the number of other attacking creatures.
Summary Execution — {2}, Sacrifice another creature: You gain 2 life and draw a card.

Captain Lannery Storm

Haste
Whenever Captain Lannery Storm attacks, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Whenever you sacrifice a Treasure, Captain Lannery Storm gets +1/+0 until end of turn.

Tectonic Giant

Whenever Tectonic Giant attacks or becomes the target of a spell an opponent controls, choose one —
• Tectonic Giant deals 3 damage to each opponent.
• Exile the top two cards of your library. Choose one of them. Until the end of your next turn, you may play that card.

Etali, Primal Storm

Whenever Etali attacks, exile the top card of each player's library, then you may cast any number of spells from among those cards without paying their mana costs.

Dragonskull Summit

Dragonskull Summit enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Skyhunter Strike Force

Flying
Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
Lieutenant — As long as you control your commander, other creatures you control have melee.

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.)

Boros Signet

Sword of the Animist

Equipped creature gets +1/+1.
Whenever equipped creature attacks, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Equip {2}

Hero of Bladehold

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Whenever Hero of Bladehold attacks, create two 1/1 white Soldier creature tokens that are tapped and attacking.

Bloodstained Mire

{T}, Pay 1 life, Sacrifice Bloodstained Mire: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

Pillarverge Pathway

Needleverge Pathway

Needleverge Pathway // Pillarverge Pathway

Marsh Flats

{T}, Pay 1 life, Sacrifice Marsh Flats: Search your library for a Plains or Swamp card, put it onto the battlefield, then shuffle.

Sacred Foundry

({T}: Add {R} or {W}.)
As Sacred Foundry enters, you may pay 2 life. If you don't, it enters tapped.

Delina, Wild Mage

Whenever Delina, Wild Mage attacks, choose target creature you control, then roll a d20.
1—14 | Create a tapped and attacking token that's a copy of that creature, except it's not legendary and it has "At end of combat, exile this creature."
15—20 | Create one of those tokens. You may roll again.

Hellrider

Haste
Whenever a creature you control attacks, Hellrider deals 1 damage to the player or planeswalker it's attacking.

Read the Bones

Scry 2, then draw two cards. You lose 2 life. (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.)

Luxury Suite

Luxury Suite enters tapped unless you have two or more opponents.
{T}: Add {B} or {R}.

Thrilling Discovery

You gain 2 life. Then you may discard two cards. If you do, draw three cards.

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.

Plains

Clifftop Retreat

Clifftop Retreat enters tapped unless you control a Mountain or a Plains.
{T}: Add {R} or {W}.

Adeline, Resplendent Cathar

Vigilance
Adeline, Resplendent Cathar's power is equal to the number of creatures you control.
Whenever you attack, for each opponent, create a 1/1 white Human creature token that's tapped and attacking that player or a planeswalker they control.

Isolated Chapel

Isolated Chapel enters tapped unless you control a Plains or a Swamp.
{T}: Add {W} or {B}.

Seize the Day

Untap target creature. After this main phase, there is an additional combat phase followed by an additional main phase.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Generous Gift

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

Aurelia, the Warleader

Flying, vigilance, haste
Whenever Aurelia attacks for the first time each turn, untap all creatures you control. After this phase, there is an additional combat phase.

Skyknight Vanguard

Flying
Whenever Skyknight Vanguard attacks, create a 1/1 white Soldier creature token that's tapped and attacking.

Spectator Seating

Spectator Seating enters tapped unless you have two or more opponents.
{T}: Add {R} or {W}.

Mountain

Isshin, Two Heavens as One

If a creature attacking causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Mishra, Claimed by Gix

Whenever you attack, each opponent loses X life and you gain X life, where X is the number of attacking creatures. If Mishra, Claimed by Gix and a creature named Phyrexian Dragon Engine are attacking, and you both own and control them, exile them, then meld them into Mishra, Lost to Phyrexia. It enters tapped and attacking.

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.

Brave the Sands

Creatures you control have vigilance.
Each creature you control can block an additional creature each combat.