msem-instigator

{2}{B}, Exile Barbed Cocoon from your graveyard: Create two 1/1 green Insect creature tokens. Activate only as a sorcery.

Barbed Reef enters tapped. When it does, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this, then you may put that card into your graveyard.)
{T}: Add {B}.
{4}{B}: Barbed Reef becomes a Jellyfish creature. (This effect lasts indefinitely.)

Barren Boneyard enters tapped.
{T}: Add {B}.
{2/B}{2/B}: Barren Boneyard becomes a 2/3 black Elemental creature with deathtouch until end of turn. It's still a land.

As Barren Desolation enters, you may pay 2 life. If you don't, Barren Desolation enters tapped.
{T}, Sacrifice Barren Desolation: Search your library for a Plains or Swamp card, put it onto the battlefield, then shuffle.

Barren Vista enters tapped.
{T}: Add {U} or {B}.
{1}, {T}: Add one mana of any color.

Whenever Barricade Watch is dealt damage, put a +1/+1 counter on it. (It must survive the damage to get the counter.)

Target creature you control gets +0/+3 and gains hexproof until end of turn.

As an additional cost to cast this spell, exile a noncreature artifact you control with mana value X until Barx leaves the battlefield or fails to resolve. X can't be 0.
[+1]: Exile the top card of your library. You may play it until you exile another card with Barx.
[–3]: Create an X/X colorless Hound artifact creature token, where X is the greatest mana value among cards exiled by Barx as you activate this ability.
[–10]: Search each player's library for any number of nonland cards with total mana value 10 or less and exile them, then those players shuffle. Cast those cards without paying their mana costs.

Choose one —
• Target creature gets +2/-1 until end of turn.
• Basat Charm deals 3 damage to target player or planeswalker.

Flying
Chosen one ({W}{U}{B}{R}{G}: Transform this permanent.)

Basin Fortress enters tapped unless you control a basic land.
{T}: Add {B} or {G}.

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast enchantment spells or to activate an ability of an enchantment.
When Bastion, Node of the Free is destroyed, return it to its owner's hand.

Enchant creature
Enchanted creature gets -2/-0.
{3}{U}{U}: Submerge enchanted creature. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

Wu Xing (Add effects based on the number of colors of mana spent to cast this spell.)
1 | Battle of Principles deals X damage to any target.
5 | When a creature or planeswalker dealt damage this way dies this turn, return it to the battlefield under your control.

When Battlemage's Disruption enters, you may return target creature to its owner's hand.
{3}{U}, Sacrifice Battlemage's Disruption: Return target creature to its owner's hand.

[progress 2-6]
[progress 7+]
Creatures you control get +2/+2 and have indestructible.

At the beginning of your upkeep, Bauble of Infinites deals 2 damage to each opponent and you gain 2 life.

(Transform this if it's not attached to a creature. Pay {1}{U} as a sorcery to unattach it.)
Enchant creature you control
Bay-Bandit's Snapper's rider gets +1/+2.
Whenever Bay-Bandit's Snapper's rider deals combat damage to a player, you draw two cards.

Whenever you cast an instant or sorcery spell, each opponent loses 1 life and Beast of Pestilence gets +1/+1 until end of turn.

Target creature you control fights target creature you don't control.

{2}{G}: Target face-down creature you control becomes a Beast with base power and toughness 5/5 until end of turn.

Damage can't be prevented this turn. Beat & Batter deals 2 damage to target player, then 2 damage to each player that's gained life this turn.

Sabotage — Whenever an opponent or permanent an opponent controls becomes the target of a spell you control, put a quest counter on Beckon Darkness.
At the beginning of your upkeep, if Beckon Darkness has four or more quest counters on it, return target creature card from your graveyard to the battlefield.

Bloodprice {2}{B}{B} (You may cast this card by sacrificing a creature and paying its bloodprice.)
Return target creature card from your graveyard to your hand. If you cast this spell for its bloodprice, return that card to the battlefield instead.

Draw a card, then reveal any number of creature or land cards from your hand. You gain that much life.