msem-instigator

Battalion — Whenever Battleborn Brute and at least two other creatures attack, Battleborn Brute gets +2/+2 until end of turn. Untap it.

Desecrate (When this creature enters, you may sacrifice an artifact or land.)
When Beastback Raider desecrates a permanent, discard your hand, then draw three cards.

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.)

When Benthic Shipcrasher enters, scry 3.

At the beginning of your upkeep, mill a card.
Whenever a creature card is put into your graveyard from anywhere, if that card has flying, you may put a flying counter on Berylscale Alaj. Repeat this process for first strike, double strike, deathtouch, hexproof, lifelink, menace, reach, trample, and vigilance.

Bjarndyr Bruiser gets +2/+2 as long as it's embattled. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Trample

Trample
Revive {5}{B} ({5}{B}, 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.)

This spell costs {1} less to cast for each card in your graveyard.
Arise {9}{B}. This ability costs {1} less to activate for each other card in your graveyard. ({9}{B}, Exile this from your graveyard as a sorcery: Create a black token copy of it that's also a Zombie and can't block.)

Reach
When this creature enters, put a -1/-1 counter on a creature you control.

When Blightbringer enters, creatures your opponents control get -1/-1 until end of turn.
Unearth {3}{B} ({3}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the end step or if it would leave the battlefield. Unearth only as a sorcery.)

{4}{R}: Blind Tunneler gets +3/+0 until end of turn.

Flying
Whenever Blizzard Dragon attacks, tap an artifact, a creature, and a land defending player controls. They don't untap during their controller's next untap step.
At the beginning of each opponent's upkeep, that player sacrifices a tapped permanent.

Whenever Blood Constrictor becomes blocked by a creature, you gain life equal to that creature's toughness.

Improve {1}{R} ({1}{R}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
As long as Bloodbelly Glutton is embattled, it has first strike, menace, and haste. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Haste
Desecrate (When this creature enters, you may sacrifice an artifact or land.)
When Bloodboil Harlequin desecrates a permanent, up to two target creatures can't block this turn.

Sacrifice another creature: Put a +1/+1 counter on target creature you control. Activate only as a sorcery.

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
When Bloodchill Risen enters, if it engorged an instant card, return target creature to its owner's hand.

Frenzy 1 (Whenever this creature attacks and isn't blocked, it gets +1/+0 until end of turn.)

Flying
{1}, Sacrifice another creature: Regenerate target Vampire.

Other Warriors you control get +2/+0.
Whenever a Warrior you control dies, Bloodshed Devotee deals 1 damage to target opponent.

Discard a card: Bloodshot Berserker gets +1/-1 until end of turn. Any player may activate this ability.

Flying
{1}, Sacrifice a creature: Put a +1/+1 counter on Bloodthirsty Manticore. It gains indestructible until end of turn. Tap it.
Surpass {4}{B}{R} ({4}{B}{R}: Transform this creature. This costs {1} less to activate for each counter on it. Activate only as a sorcery.)

Whenever a creature dies, put a +1/+1 counter on Bog Apex.