Swamp

Castle Locthwain

Castle Locthwain enters tapped unless you control a Swamp.
{T}: Add {B}.
{1}{B}{B}, {T}: Draw a card, then you lose life equal to the number of cards in your hand.

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.)

Beloved Chaplain

Crimson Acolyte

Protection from red
{W}: Target creature gains protection from red until end of turn.

Shadows' Lair

(Transforms from Grasping Shadows.)
{T}: Add {B}.
{B}, {T}, Remove a dread counter from Shadows' Lair: You draw a card and you lose 1 life.

Grasping Shadows

Whenever a creature you control attacks alone, it gains deathtouch and lifelink until end of turn. Put a dread counter on Grasping Shadows. Then if there are three or more dread counters on it, transform it.

Grasping Shadows // Shadows' Lair

Aven Squire

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

Plains

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.)

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.

Akrasan Squire

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

Battlefield Forge

{T}: Add {C}.
{T}: Add {R} or {W}. Battlefield Forge deals 1 damage to you.

Fervent Charge

Whenever a creature you control attacks, it gets +2/+2 until end of turn.

Bloodfell Caves

Bloodfell Caves enters tapped.
When Bloodfell Caves enters, you gain 1 life.
{T}: Add {B} or {R}.

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.

Tempered in Solitude

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

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.)

Nomad Outpost

Nomad Outpost enters tapped.
{T}: Add {R}, {W}, or {B}.

Duty-Bound Dead

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

Caves of Koilos

{T}: Add {C}.
{T}: Add {W} or {B}. Caves of Koilos deals 1 damage to you.

Mountain

Archetype of Aggression

Creatures you control have trample.
Creatures your opponents control lose trample and can't have or gain trample.

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}.

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.