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.

Sigiled Paladin

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

Aven Squire

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

Wall of Omens

Defender
When Wall of Omens enters, draw a card.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Angelic Benediction

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

Akrasan Squire

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

Siege Striker

Double strike (This creature deals both first-strike and regular combat damage.)
Whenever Siege Striker attacks, you may tap any number of untapped creatures you control. Siege Striker gets +1/+1 until end of turn for each creature tapped this way.

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.)

Soltari Trooper

Shadow (This creature can block or be blocked by only creatures with shadow.)
Whenever Soltari Trooper attacks, it gets +1/+1 until end of turn.

Plains

Spirit en-Dal

Shadow (This creature can block or be blocked by only creatures with shadow.)
Forecast — {1}{W}, Reveal Spirit en-Dal from your hand: Target creature gains shadow until end of turn. (Activate only during your upkeep and only once each turn.)

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.)

Thriving Heath

Thriving Heath enters tapped. As it enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

Cathedral of War

Cathedral of War enters tapped.
Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
{T}: Add {C}.

Sigil of Valor

Whenever equipped creature attacks alone, it gets +1/+1 until end of turn for each other creature you control.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Battlegrace Angel

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

Soltari Foot Soldier

Shadow (This creature can block or be blocked by only creatures with shadow.)

Duelist's Heritage

Whenever one or more creatures attack, you may have target attacking creature gain double strike until end of turn.

First Sliver's Chosen

Sliver creatures you control have exalted. (Whenever a creature you control attacks alone, it gets +1/+1 until end of turn for each instance of exalted among permanents you control.)

Fencing Ace

Double strike (This creature deals both first-strike and regular combat damage.)