msem-instigator

Align X (Choose modes with total ★ less than or equal to X. You may choose modes multiple times.)
• ★ — Bloodstained Calamity deals 1 damage to each creature, player, and planeswalker.
• ★★ — Return target instant or sorcery card from your graveyard to your hand. Exile Bloodstained Calamity.
• ★★★★★ — Bloodstained Calamity deals 10 damage to any target.

Bloodstone Halls enters tapped unless you control two or more black and/or red permanents.
{T}: Add {B} or {R}.

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

Haste
Bloodvenge Berserker doesn't untap during its controller's untap step.
Once each turn, when an opponent is dealt damage by another source you control, you may untap Bloodvenge Berserker.

At the beginning of each player's end step, if they aren't horrific, Bloody Valentine deals 2 damage to that player. (You're horrific as long as you've sacrificed a permanent or discarded a card this turn.)

For each Aura you control, create a token that's a copy of that Aura.

You may have Blurry Counterpart enter as a copy of any creature on the battlefield.
Mirage {1}{U} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Target creature gets +2/+2 until end of turn.
Fuse (You may cast one or both halves of this card from your hand.)

Whenever another creature you control enters, you may have it gain haste. If you do, return it to its owner's hand at the beginning of the next end step.

Menace
When Bogborn Exorcist enters, 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.

At the beginning of your upkeep, you may pay 3 life. If you do, create a 2/1 red Lizard creature token with frenzy 2. (Whenever it attacks and isn't blocked, it gets +2/+0 until end of turn.)

Each creature you control gets +1/+1 for each permanent attached to it.

Damage can't be prevented.
At the beginning of your upkeep, Bomb Juggler deals 3 damage to target player chosen at random.

Boneyard Pass enters tapped unless you control a basic land.
{T}: Add {W} or {B}.

At the beginning of your upkeep, sacrifice a non-Snake creature or Boon of the Pacts. Then create a 1/1 black Snake creature token with deathtouch.
At the beginning of your draw step, draw an additional card.
Spells you cast cost {1} less to cast.

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

Your life total becomes 20.
Coalesce {8}{W}{W}{W}{W} (You may cast this from your graveyard for {8}{W}{W}{W}{W}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Born Anew's power and toughness are each equal to your life total.

Whenever a creature you control deals combat damage to a player, you may sacrifice it. If you do, draw cards equal to that creature's power.

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, it deals 3 damage to any target. Scry 1.

For each creature token you control, create a token that's a copy of that creature.

{B}, {T}: Post a bounty on target permanent. (Put a bounty counter on that permanent. It has “When this permanent is put into a graveyard from the battlefield, each opponent draws a card” as long as it has a bounty counter on it.)
{B}, {T}, Pay 2 life: Destroy target creature with a bounty counter on it.

Create an X/X green and blue Plant creature token, where X is the number of differently named lands you control.

If you would draw a card, instead exile the top three cards of your library face down. You may look at those cards. Put a card exiled with Brainstorming Session into its owner's hand.
{X}{X}{U}, Sacrifice Brainstorming Session: Put X cards exiled with it into their owner's hand.

Gain control of target permanent. (Cast a copy of this spell once while this creature is on the battlefield.)

Archive 5 (As this enters, shuffle the top five cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever a player discards a card, draw a card from the archived library.