msem-instigator

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

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

Creatures you control that have been dealt damage this turn get +2/+0.
When Bloodspawn enters the battlefield, it deals 1 damage to target creature you control.

Flying, deathtouch
When Bloodsucking Pihuchen enters the battlefield, choose a nonland card name.
Whenever a permanent with the chosen name enters the battlefield, each opponent loses 1 life and you gain 1 life.

When Blossom-Ash Trance enters the battlefield, you gain 3 life.
At the beginning of each end step, if you gained 3 or more life this turn, draw a card.

When Blossom-Sower Witch enters the battlefield, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
Whenever you sacrifice a permanent, you gain 1 life.

Flying
When Blossoming Hatchling enters the battlefield, create a Treasure token.

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

Menace
When Bogborn Exorcist enters the battlefield, you may discard a card. When you do, exile target instant or sorcery card with mana value 3 or less from an opponent's graveyard. Copy that card. You may cast the copy without paying its mana cost.

Enchant creature
When Bogfume Pact enters the battlefield, each opponent sacrifices a creature.
When enchanted creature dies, return it to its owner's hand.

Flying
When Bogsnatcher Drake enters the battlefield, create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

When Bone Pit Raptor enters the battlefield, other creatures you control get +1/-1 until end of turn.
Revive {2}{R} ({2}{R}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Vigilance, trample
When Border Guardian enters the battlefield, return a creature you control to its owner's hand.

When Borderland Garrison enters the battlefield, it deals 1 damage to up to one target creature and 1 damage to you.

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

Eureka! (At the beginning of each end step, you get a research counter if you cast a spell this turn. Then if you have eight or more research counters, remove them and create a Masterpiece token of your choice.)
When Bottled Lightning enters the battlefield, it deals 3 damage to any target. Scry 1.

Flying, prowess
When Bound Watcher enters the battlefield, conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

When Boundary Hallowblade enters the battlefield, 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.”

Harmony — Create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”
When Bouquet Singer enters the battlefield, harmonize. (Trigger up to one harmony of one permanent you control.)

When Braenid Nomad enters the battlefield, draw two cards, then discard a card.

Enchant creature
When Bramble Armor enters the battlefield, put a +1/+1 counter on enchanted creature.
{G}, Sacrifice Bramble Armor: Enchanted creature gains indestructible end of turn. Tap it.

When Brand New Species enters the battlefield, create a tapped 3/2 green Horror creature token.
Augmented — At the beginning of each end step, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on up to one target Horror you control.

Enchant creature you control
When Brawnsurge enters the battlefield, enchanted creature deals damage equal to its power to up to one target creature an opponent controls.
Enchanted creature gets +1/+1 and has trample.

When Breaker of Secrets enters the battlefield, each player mills three cards from each of their libraries.
Recite {U} (You may cast this creature from your graveyard for its recite cost. If you do, exile it when it enters the battlefield or if it would leave the battlefield.)

When Briarform Apothecary enters the battlefield, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
Sacrifice a token: Briarform Apothecary gets +2/+2 until end of turn.