Samurai's Katana

Job select (When this Equipment enters, create a 1/1 colorless Hero creature token, then attach this to it.)
Equipped creature gets +2/+2, has trample and haste, and is a Samurai in addition to its other types.
Murasame — Equip {5}

Eiganjo Exemplar

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

Voltage Surge

As an additional cost to cast this spell, you may sacrifice an artifact.
Voltage Surge deals 2 damage to target creature or planeswalker. If this spell's additional cost was paid, Voltage Surge deals 4 damage instead.

Stone Quarry

This land enters tapped.
{T}: Add {R} or {W}.

Cloudsteel Kirin

Flying
Equipped creature has flying and "You can't lose the game and your opponents can't win the game."
Reconfigure {5} ({5}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Kami's Flare

Kami's Flare deals 3 damage to target creature or planeswalker. Kami's Flare also deals 2 damage to that permanent's controller if you control a modified creature. (Equipment, Auras you control, and counters are modifications.)

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.

Boros Guildgate

Imperial Oath

Create three 2/2 white Samurai creature tokens with vigilance. Scry 3.

Imperial Subduer

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

Mountain

Wind-Scarred Crag

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {R} or {W}.

Banishing Slash

Destroy up to one target artifact, enchantment, or tapped creature. Then if you control an artifact and an enchantment, create a 2/2 white Samurai creature token with vigilance.

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.

Plains

Seven-Tail Mentor

When this creature enters or dies, put a +1/+1 counter on target creature or Vehicle you control.

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.

Thundering Raiju

Haste
Whenever this creature attacks, put a +1/+1 counter on target creature you control. Then this creature deals X damage to each opponent, where X is the number of modified creatures you control other than this creature. (Equipment, Auras you control, and counters are modifications.)

Light the Way

Choose one —
• Put a +1/+1 counter on target creature or Vehicle. Untap it.
• Return target permanent you control to its owner's hand.

Eiganjo Uprising

Create X 2/2 white Samurai creature tokens with vigilance. They gain menace and haste until end of turn.
Each opponent creates X minus one 2/2 white Samurai creature tokens with vigilance.

Reinforced Ronin

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