msem-instigator

{T}: Until end of turn, target land is every basic land type in addition to its other types and its name becomes Morphic Sea.

Armed — Beragnian Savage gets +1/+0 and has first strike as long as it's equipped.

Flying
Sacrifice six Swamps: Return Berbarus Unsealed from your graveyard to the battlefield with an indestructible counter on it. You draw six cards and you lose 6 life.

Prevent all combat damage that would be dealt to and dealt by Bereaved Aristocrat.
Unveil {2}{W}{U} ({2}{W}{U}: Transform this. Unveil only as a sorcery.)

When Bessie's Brood enters the battlefield, it fights target creature. (If there are no other creatures, it eats itself.)

When Bestower of Blooms dies, create an X/X green Plant Knight creature token, where X is Bestower of Blooms's power.

When Bezoarbeast dies, each opponent loses 2 life and you create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)

{T}: Add one mana of any color a basic land you control could produce.

Menace
When Bit Player dies, it deals 1 damage to each opponent.

Desecrate (When this creature enters the battlefield, you may sacrifice an artifact or land.)
When Bitter Wanderer desecrates a permanent, each opponent loses 2 life and you gain 2 life.

When Bjarndyr Militant enters the battlefield, return target Aura card or card with fabled from your graveyard to your hand.

Trample
Other Bears you control get +2/+2.

Deathtouch
{B}, Pay 1 life: Add one mana of any color. Activate this ability only once each turn.

Lifelink
{T}, Pay 4 life or sacrifice another permanent: Draw a card.

Flying
Whenever Blade of Reckoning deals combat damage to a player, that player sacrifices an untapped permanent.

{1}{R/W}: Untap Blade of the Long Night.

Poisonous 1 (Whenever this creature deals combat damage to a player, that player gets a poison counter.)
Blade of the Serpent gets +1/+1 as long as an opponent is poisoned.

Advance {1}{R}{W}{B} (Cast this for {1}{R}{W}{B} to advance it as it enters. {1}{R}{W}{B}: Advance this as a sorcery.)
Whenever Blastburn Angel advances, it gets +1/+1 and gains flying until end of turn. It deals 1 damage to each other creature.

When Bleeding-Edge Garroter dies, if it was in a pack, you draw a card and you lose 1 life. (Two or more creatures you control with equal power are in a pack.)

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.)

When Blighting Ooze enters the battlefield, put a -1/-1 counter on each of up to X target creatures.
As long as Blighting Ooze is on the battlefield, it has all activated abilities of each creature with a -1/-1 counter on it.

Sacrifice a creature: Put a +1/+1 counter on Blightroot.
Sacrifice a land: Blightroot gains indestructible until end of turn.

Flash
Blind Blackguard can't block.
When Blind Blackguard enters the battlefield, target player draws a card, then reveals their hand. You choose a nonland card from that player's hand, then that player puts the chosen card on the bottom of their library.

Breach (Whenever this deals combat damage to a player, you may have it become an Aura Curse until your next turn. Attach it to that player.)
At the beginning of your end step, each cursed opponent loses 2 life unless they discard a card.

Lifelink
Revive {3}{B} ({3}{B}, Exile this card from your graveyard: Create a token that's a copy of this card, except it has no mana cost. Activate this ability only any time you could cast a sorcery.)