The Wandering Emperor

Flash
As long as The Wandering Emperor entered this turn, you may activate her loyalty abilities any time you could cast an instant.
+1: Put a +1/+1 counter on up to one target creature. It gains first strike until end of turn.
−1: Create a 2/2 white Samurai creature token with vigilance.
−2: Exile target tapped creature. You gain 2 life.

Konda's Hatamoto

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)
As long as you control a legendary Samurai, Konda's Hatamoto gets +1/+2 and has vigilance. (Attacking doesn't cause this creature to tap.)

Hand of Honor

Protection from black
Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)

Sensei Golden-Tail

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)
{1}{W}, {T}: Put a training counter on target creature. That creature gains bushido 1 and becomes a Samurai in addition to its other creature types. Activate only as a sorcery.

Call to Glory

Untap all creatures you control. Samurai creatures you control get +1/+1 until end of turn.

Goro-Goro, Disciple of Ryusei

{R}: Creatures you control gain haste until end of turn.
{3}{R}{R}: Create a 5/5 red Dragon Spirit creature token with flying. Activate only if you control an attacking modified creature. (Equipment, Auras you control, and counters are modifications.)

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.)

Kentaro, the Smiling Cat

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)
You may pay {X} rather than pay the mana cost for Samurai spells you cast, where X is that spell's mana value.

Flowering of the White Tree

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

Samurai of the Pale Curtain

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)
If a permanent would be put into a graveyard, exile it instead.

Araba Mothrider

Flying
Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)

Devoted Retainer

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)

Ronin Houndmaster

Haste
Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)

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.

Legion's Initiative

Red creatures you control get +1/+0.
White creatures you control get +0/+1.
{R}{W}, Exile Legion's Initiative: Exile all creatures you control. At the beginning of the next combat, return those cards to the battlefield under their owner's control and those creatures gain haste until end of turn.

Brave the Sands

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

Rising of the Day

Creatures you control have haste.
Legendary creatures you control get +1/+0.

Nagao, Bound by Honor

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)
Whenever Nagao, Bound by Honor attacks, Samurai creatures you control get +1/+1 until end of turn.

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.

Hand of Cruelty

Protection from white
Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)

Takeno, Samurai General

Bushido 2 (Whenever this creature blocks or becomes blocked, it gets +2/+2 until end of turn.)
Each other Samurai creature you control gets +1/+1 for each point of bushido it has.

The Eternal Wanderer

No more than one creature can attack The Eternal Wanderer each combat.
+1: Exile up to one target artifact or creature. Return that card to the battlefield under its owner's control at the beginning of that player's next end step.
0: Create a 2/2 white Samurai creature token with double strike.
−4: For each player, choose a creature that player controls. Each player sacrifices all creatures they control not chosen this way.