Stalwart Valkyrie

You may pay {1}{W} and exile a creature card from your graveyard rather than pay this spell's mana cost.
Flying

Ancestral Katana

Whenever a Samurai or Warrior you control attacks alone, you may pay {1}. When you do, attach this Equipment to it.
Equipped creature gets +2/+1.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Call to Glory

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

Goblin Champion

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

Reckless Ogre

Whenever this creature attacks alone, it gets +3/+0 until end of turn.

Deconstruction Hammer

Equipped creature gets +1/+1 and has "{3}, {T}, Sacrifice Deconstruction Hammer: Destroy target artifact or enchantment."
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Eiganjo Exemplar

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

Imperial Subduer

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

Peter Parker's Camera

This artifact enters with three film counters on it.
{2}, {T}, Remove a film counter from this artifact: Copy target activated or triggered ability you control. You may choose new targets for the copy.

Plains

Guardians of Akrasa

Defender (This creature can't attack.)
Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)

Resolute Strike

Target creature gets +2/+2 until end of turn. If it's a Warrior, you may attach an Equipment you control to it.

Akki Ronin

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

Shatterskull Recruit

Menace (This creature can't be blocked except by two or more creatures.)

Aven Squire

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

Mountain

Akrasan Squire

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

Kami of False Hope

Sacrifice this creature: Prevent all combat damage that would be dealt this turn.

Flare of Faith

Target creature gets +2/+2 until end of turn. If it's a Human, instead it gets +3/+3 and gains indestructible until end of turn.

Wrecking Crew

Reach (This creature can block creatures with flying.)
Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

Lunk Errant

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