msem-instigator

Other Knights and Soldiers you control get +1/+0.
Cowards can't block Knights and Soldiers you control.
When Belmord Bloodcurdler enters, target creature an opponent controls becomes a Coward in addition to its other types. (This effect last indefinitely.)

Aetherize each permanent you control. Exile Beneath the Horizon. (To aetherize a permanent, create a token that's a copy of it, then exile that token.)

Armed — Beragnian Blacksmith can't attack unless it's equipped.
When Beragnian Blacksmith enters, you may pay {2}. If you do, arm it. (Create a colorless Equipment artifact token with “Equipped creature gets +1/+0” and equip {2}, then attach it to this creature.)

Blazing Offerings deals 4 damage to target creature or planeswalker.

Blessed Barrage deals 5 damage divided as you choose among any number of attacking or blocking creatures.

Blighted Unicorn can't block.
Ride {3}{B} ({3}{B}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

{T}: Add {C}.
Dominance — {1}, {T}: Blistering Boneyard deals 1 damage to each opponent. Activate only if you control the creature with the greatest power or tied for the greatest power.

When Bloodbriar Acolyte dies, draw a card. Each opponent loses 1 life.

Trample
{T}, Sacrifice another creature: You gain 3 life.
Whenever another creature you control dies, put a +1/+1 counter on Bloodbriar Archdruid.

Deathtouch
{T}, Sacrifice another creature: Add two mana of any one color.

Enchant creature
When Bloodbriar Blessing enters, draw a card.
Enchanted creature gets +2/+2 and has menace.

Sacrifice another creature: Put a +1/+1 counter on target creature you control. Activate only as a sorcery.

Bloodsand Gulch enters tapped unless you control another Desert.
{T}: Add {B} or {R}.

When Bloodsoaked Blades enters, creatures you control get +2/+0 until end of turn.
Equipped creature gets +1/+1.
Equip {1}

Enchant land
Enchanted land has “{T}: Each opponent loses 2 life.”

Haste
Bloodvenge Berserker doesn't untap during its controller's untap step.
Once each turn, when an opponent is dealt damage by another source you control, you may untap Bloodvenge Berserker.

Blooming Needles enters tapped unless you control another Desert.
{T}: Add {R} or {G}.

Assault {1}{B} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
When Bone Mesa Marauder assaults, it gains flying until end of turn.

Vigilance, deathtouch
Civilized — When Bordermakers enters, if you control a creature, an artifact, and an enchantment, each opponent loses 4 life and you gain 4 life.

{G}, {T}, Remove a +1/+1 counter from a creature you control: Create a 2/2 green Ox creature token.

Assault {R} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
When Borsuppa Outrider assaults, it deals 2 damage to each opponent.

Menace (This creature can't be blocked except by two or more creatures.)
Assault {R} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)

When Boundary Hallowblade enters, create a white Aura enchantment token named Consecration Blessing attached to target land. The token has enchant land and “Enchanted land is named Hallowed Ground and has indestructible.”

Create an X/X green and blue Plant creature token, where X is the number of differently named lands you control.

Trample
Whenever Breaker of Cities deals combat damage to a player, create a 1/1 white Soldier creature token with vigilance.
Crew 1 (Tap any number of creatures you control with total power 1 or greater: This Vehicle becomes an artifact creature until end of turn.)