msem-instigator

(Transform this if it's not attached to a creature. Pay {2}{B}{B} as a sorcery to unattach it.)
Enchant creature you control
Belmord Blood-Coach's rider gets +3/+3 and has deathtouch.
Whenever Belmord Blood-Coach's rider attacks, you may return target creature card with mana value less than its rider's power from your graveyard to the battlefield tapped.

Enchant creature
At the beginning of the upkeep of enchanted creature's controller, Betrayer's Mantle deals 3 damage to that player.

Bigroot Valley enters tapped.
{T}: Add {R} or {G}.
{1}, {T}: Add one mana of any color.

When Bio-Sequencer enters, conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)
{1}, {T}, Sacrifice Bio-Sequencer: Add one mana of any color.

When Blackwall's Edge enters, if you control four or more lands, you may have each player conjure a card named Data-Point into their hand. (It's a sorcery that costs {2} with “Draw a card.”)
{T}: Add {C}.
When Blackwall's Edge is destroyed, return it to its owner's hand.

At the beginning of your upkeep, if Blade of Ancestors isn't attached to a creature, create a 1/1 white Soldier creature token, then attach Blade of Ancestors to it.
Equipped creature gets +1/+1.
Equip {2}

({T}: Add {U}, {B}, or {R}.)
Bleak Dominion enters tapped.

Bleak Shoreline enters tapped unless you control an Island.
{T}: Add {W} or {B}.

Bleakrealm Moor enters tapped unless you played it from exile.
{T}: Add {B} or {R}.

Enchant land
Whenever enchanted land is tapped for mana, its controller adds two mana in any combination of colors (in addition to the mana the land produces.)

({T}: Add {W} or {B}.)
As Blessed Mausoleum enters, you may pay {1}. If you don't, Blessed Mausoleum enters tapped.

{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.

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

({T}: Add {R}.)
Bloodriver enters tapped.
When Bloodriver enters, target creature you control gains haste until end of turn.

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

Bloodstone Halls enters tapped unless you control two or more black and/or red permanents.
{T}: Add {B} or {R}.

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

Blooming Vista enters tapped.
{T}: Add {R} or {G}.
{1}, {T}: Add one mana of any color.

When Blossoming Expanse enters, you may put a basic land card from your hand onto the battlefield tapped.
{1}, {T}: Add one mana of any color.

Blossoming Sands enters tapped.
When Blossoming Sands enters, you gain 1 life.
{T}: Add {G} or {W}.

Trample
{T}: Add {C}.
At the beginning of your upkeep, you may pay {2}. When you do, Blundering Clocktower becomes a creature in addition to its other types until the beginning of your next end step. End the turn.

Equipped creature has menace.
Equip {0} ({0}: Attach to target creature you control. Equip only as a sorcery.)

({T}: Add {U} or {R}.)
Boiling Ridge enters tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

Equipped creature gets +1/+0.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)