msem-instigator

Whenever a creature you control dies, you may search your library for a creature card with lesser mana value, put it onto the battlefield tapped, then shuffle. Do this only once during each of your turns.

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.)

Flash
Lifelink
When this creature enters, counter target spell unless its controller pays {1} or 3 life.

Siphon (Each -1/-1 counter you put on your creatures up to their remaining toughness while casting this pays for {1}.)
Destroy target creature or planeswalker.

Flying
Belmord can't block.
{1}{B}: Create a 1/1 black Bat creature token with flying and “This creature can't block.” Activate only if a player gained or lost life this turn and only once each turn.

Choose target creature with the greatest power or tied for the greatest power, then destroy all other creatures.

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.)

Destroy target artifact or enchantment.
Draw a card.

Mill four cards, then you may return a creature or planeswalker card from your graveyard to your hand.
As long as Beneath the Zhedina is in your graveyard, other cards in your graveyard can't be the target of spells or abilities your opponents control.

Whenever Benevolent Host attacks, if you control another Angel or Nephilim, Benevolent Host gains flying until end of turn. Surveil 1.

Flying
When Benevolent Malach enters, create a 1/1 colorless Construct artifact creature token.
Sacrifice Benevolent Malach: Artifacts you control gain indestructible until end of turn.

When Benign Whisper enters, return another target creature to its owner's hand.

[+1]: Creatures you control get +1/+0 and gain haste until end of turn.
[0]: Bennett Brooks deals 2 damage to each opponent. If you have an insight counter, create two Treasure tokens.
[0]: You get an insight counter.
[–2]: Sacrifice an artifact. If you do, return target artifact card from your graveyard to the battlefield.

When Benthic Alchemist enters, draw a card, then discard a card, then mill a card.
Whenever you cast an instant or sorcery spell, create a 1/1 colorless Elemental creature token. It gains haste until end of turn.

When Benthic Shipcrasher enters, scry 3.

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

When Benthic Tidebreaker enters, reveal the top card of each player's library and exile one of those cards. You may play that card for as long as it remains exiled, and you may spend blue mana as though it were mana of any color to cast it.
Evoke {1}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

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.)

Tap up to two target creatures. They don't untap during their controller's next untap step.
Reprise {3}{U} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Whenever Beragnian Brawlmaster or another Warrior you control enters, that Warrior fights target creature an opponent controls.
{R}{W}: Target Warrior creature gets +1/+1 until end of turn.

Armed — Whenever Beragnian Intimidator attacks, if it's equipped, target creature can't block this turn.

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.

Target opponent reveals their hand. You choose a nonland permanent card from it. That player discards that card.