Goblin Champion

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

Akki Ronin

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

Selfless Samurai

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

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.

Knight of Infamy

Protection from white (This creature can't be blocked, targeted, dealt damage, or enchanted by anything white.)
Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)

Alesha, Who Smiles at Death

First strike
Whenever Alesha attacks, you may pay {W/B}{W/B}. If you do, return target creature card with power 2 or less from your graveyard to the battlefield tapped and attacking.

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.

Knight of Glory

Protection from black (This creature can't be blocked, targeted, dealt damage, or enchanted by anything black.)
Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)

Servant of Nefarox

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

Sublime Archangel

Flying
Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
Other creatures you control have exalted. (If a creature has multiple instances of exalted, each triggers separately.)

Lunk Errant

Whenever this creature attacks alone, it gets +1/+1 and gains trample until end of turn.

Eiganjo Exemplar

Whenever a Samurai or Warrior you control attacks alone, 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.

Nefarox, Overlord of Grixis

Flying
Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
Whenever Nefarox attacks alone, defending player sacrifices a creature of their choice.

Duty-Bound Dead

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
{3}{B}: Regenerate this creature. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Imperial Subduer

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