msem-instigator

Advance {1}{R} (Cast this for {1}{R} to advance it as it enters. {1}{R}: Advance this as a sorcery.)
Whenever Blitz Breaker advances, its power becomes equal to the amount of noncombat damage that's been dealt to your opponents this turn. (This effect lasts indefinitely.)

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Blood-Tithe Harpy enters, target player loses 1 life and you gain 1 life.

Lifelink
{1}{B}, Sacrifice Bloodbond Ritualist: Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.

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

Bloodcrazed Acolyte enters with a +1/+1 counter on it for each player who lost life this turn.

Whenever Bloodcrazed Instigator attacks, target Rebel creature you control gains first strike until end of turn.

Haste
When Bloodfury Warlord enters or dies, it deals 2 damage to each player.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Bloodied Twinblade dies, scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)

{T}: Choose a color of a card in your graveyard. Add one mana of that color.

Deathtouch

{G}, {T}: Put a +1/+1 counter on Bloodleaf Tracker for each creature that entered this turn.

{T}: Another target Warrior you control gets +1/+0 and gains haste until end of turn.

Whenever Bloodthirsty Insurgent attacks, it gets +2/+0 until end of turn.

Menace
Revive {1}{R} ({1}{R}, 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.)

Flying
When Blossoming Hatchling enters, create a Treasure token.

First strike
{T}: Bogclaw Sniper deals 2 damage to target blocking creature.

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

When Bone Pit Raptor enters, 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.)

Whenever another creature you control dies, you may pay {1}. If you do, scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Sacrifice Bonetooth Darter: Counter target instant, planeswalker, or sorcery spell unless its controller pays {1}.

When Border Seeker dies, search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then you gain 1 life for each land you control.

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.)

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

Whenever Bourasan Street Watch attacks, you may pay {W}. If you do, Bourasan Street Watch gains indestructible until end of turn.