Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Selfless Samurai

Whenever a Samurai or Warrior you control attacks alone, it gains lifelink until end of turn.
Sacrifice Selfless Samurai: Another target creature you control gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Norika Yamazaki, the Poet

Vigilance
Whenever a Samurai or Warrior you control attacks alone, you may cast target enchantment card from your graveyard this turn.

Curiosity

Enchant creature
Whenever enchanted creature deals damage to an opponent, you may draw a card.

Dragon Cultist

Commander creatures you own have "At the beginning of your end step, if a source you controlled dealt 5 or more damage this turn, create a 4/4 red Dragon creature token with flying."

Finest Hour

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
Whenever a creature you control attacks alone, if it's the first combat phase of the turn, untap that creature. After this phase, there is an additional combat phase.

Netherborn Altar

{T}, Put a soul counter on Netherborn Altar: Put your commander into your hand from the command zone. Then you lose 3 life for each soul counter on Netherborn Altar.

Bastion Protector

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

Deflecting Swat

If you control a commander, you may cast this spell without paying its mana cost.
You may choose new targets for target spell or ability.

Noble Hierarch

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
{T}: Add {G}, {W}, or {U}.

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.)

Peerless Samurai

Menace (This creature can't be blocked except by two or more creatures.)
Whenever a Samurai or Warrior you control attacks alone, the next spell you cast this turn costs {1} less to cast.

Galea, Kindler of Hope

Vigilance
You may look at the top card of your library any time.
You may cast Aura and Equipment spells from the top of your library. When you cast an Equipment spell this way, it gains "When this Equipment enters, attach it to target creature you control."

Gift of Doom

Enchant creature
Enchanted creature has deathtouch and indestructible.
Morph—Sacrifice another creature. (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
As Gift of Doom is turned face up, you may attach it to a creature.

Inspiring Leader

Commander creatures you own have "Creature tokens you control get +2/+2."

Rafiq of the Many

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
Whenever a creature you control attacks alone, it gains double strike until end of turn.

Astor, Bearer of Blades

When Astor, Bearer of Blades enters, look at the top seven cards of your library. You may reveal an Equipment or Vehicle card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
Equipment you control have equip {1}.
Vehicles you control have crew 1.

Bloodsworn Steward

Flying
Commander creatures you control get +2/+2 and have haste.

Angelic Exaltation

Whenever a creature you control attacks alone, it gets +X/+X until end of turn, where X is the number of creatures you control.

Asari Captain

Haste
Whenever a Samurai or Warrior you control attacks alone, it gets +1/+0 until end of turn for each Samurai or Warrior you control.

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.)

Ironsoul Enforcer

Whenever Ironsoul Enforcer or a commander you control attacks alone, return target artifact card from your graveyard to the battlefield.

Tempered in Solitude

Whenever a creature you control attacks alone, exile the top card of your library. You may play that card this turn.

Guardian Augmenter

Flash
Commander creatures you control get +2/+2.
Commanders you control have hexproof.

Kediss, Emberclaw Familiar

Whenever a commander you control deals combat damage to an opponent, it deals that much damage to each other opponent.
Partner (You can have two commanders if both have partner.)

Deadly Rollick

If you control a commander, you may cast this spell without paying its mana cost.
Exile target creature.

Commander's Plate

Equipped creature gets +3/+3 and has protection from each color that's not in your commander's color identity.
Equip commander {3}
Equip {5}

Genesis Storm

When you cast this spell, copy it for each time you've cast your commander from the command zone this game.
Reveal cards from the top of your library until you reveal a nonland permanent card. You may put that card onto the battlefield. Then put all cards revealed this way that weren't put onto the battlefield on the bottom of your library in a random order.

Biowaste Blob

Oozes you control get +1/+1.
At the beginning of your upkeep, if you control a commander, create a token that's a copy of Biowaste Blob.

Forge of Heroes

{T}: Add {C}.
{T}: Choose target commander that entered this turn. Put a +1/+1 counter on it if it's a creature and a loyalty counter on it if it's a planeswalker.

Champion's Helm

Equipped creature gets +2/+2.
As long as equipped creature is legendary, it has hexproof. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Imperial Subduer

Whenever a Samurai or Warrior you control attacks alone, tap target creature you don't control.

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.

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.

Hellkite Courser

Flying
When Hellkite Courser enters, you may put a commander you own from the command zone onto the battlefield. It gains haste. Return it to the command zone at the beginning of the next end step.

Security Bypass

Enchant creature
As long as enchanted creature is attacking alone, it can't be blocked.
Enchanted creature has "Whenever this creature deals combat damage to a player, it connives." (Its controller draws a card, then discards a card. If they discarded a nonland card, they put a +1/+1 counter on this creature.)

Ignoble Hierarch

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
{T}: Add {B}, {R}, or {G}.

Najeela, the Blade-Blossom

Whenever a Warrior attacks, you may have its controller create a 1/1 white Warrior creature token that's tapped and attacking.
{W}{U}{B}{R}{G}: Untap all attacking creatures. They gain trample, lifelink, and haste until end of turn. After this phase, there is an additional combat phase. Activate only during combat.

Heiko Yamazaki, the General

Trample
Whenever a Samurai or Warrior you control attacks alone, you may cast target artifact card from your graveyard this turn.

Criminal Past

Commander creatures you own have menace and "This creature gets +X/+0, where X is the number of creature cards in your graveyard." (A creature with menace can't be blocked except by two or more creatures.)

Akki Ronin

Whenever a Samurai or Warrior you control attacks alone, you may discard a card. If you do, draw a card.

Agent of the Shadow Thieves

Commander creatures you own have "Whenever this creature attacks a player, if no opponent has more life than that player, put a +1/+1 counter on this creature. It gains deathtouch and indestructible until end of turn."

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}

Flaming Fist

Commander creatures you own have "Whenever this creature attacks, it gains double strike until end of turn."

Cultist of the Absolute

Commander creatures you own get +3/+3 and have flying, deathtouch, "Ward—Pay 3 life," and "At the beginning of your upkeep, sacrifice a creature."