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.)

Eater of Virtue

Whenever equipped creature dies, exile it.
Equipped creature gets +2/+0.
As long as a card exiled with Eater of Virtue has flying, equipped creature has flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, protection, reach, trample, and vigilance.
Equip {1}

Search the Premises

Whenever a creature attacks you or a planeswalker you control, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

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.

Fumiko the Lowblood

Fumiko has bushido X, where X is the number of attacking creatures. (Whenever this creature blocks or becomes blocked, it gets +X/+X until end of turn.)
Creatures your opponents control attack each combat if able.

Command Tower

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

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.)

Imperial Subduer

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

Arcane Signet

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.

Eiganjo Exemplar

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

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.)

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.)

Boros Garrison

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {R}{W}.

Access Tunnel

{T}: Add {C}.
{3}, {T}: Target creature with power 3 or less can't be blocked this turn.

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.

Akki Ronin

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

Plains

Tempered in Solitude

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

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.

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.

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.

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.

Mountain

Sol Ring

Wind-Scarred Crag

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

Risona, Asari Commander

Haste
Whenever Risona deals combat damage to a player, if it doesn't have an indestructible counter on it, put an indestructible counter on it.
Whenever combat damage is dealt to you, remove an indestructible counter from Risona.