msem-instigator

Beachhead Partisan has first strike as long as it's attacking.
When Beachhead Partisan enters, it deals X damage to any target, where X is the number of tapped creatures you control.

When Bearer of the Lantern enters, you gain 3 life.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Whenever an artifact or enchantment you control enters, you may detain target nonland permanent. (Until your next turn, that permanent can't attack or block and its activated abilities can't be activated.)

Whenever you detain a permanent, you gain life equal to that permanent's mana value.

Auras and Equipment you control have indestructible.
Whenever Bearidge Marshall attacks, you may create a white Aura enchantment token named Arrest attached to target creature. It has enchant creature and “Enchanted creature can't attack or block, and its activated abilities can't be activated.”

{2}, {T}: Tap target creature.

Choose one —
• Search your library for a card with harmony, reveal it, put it into your hand, then shuffle.
• Harmonize twice. (To harmonize, trigger up to one harmony of a permanent you control.)

If you control ten or more nonland permanents, you get an emblem with “At the beginning of your end step, return target permanent card from your graveyard to the battlefield.”
Destroy all nonland permanents.

At the beginning of combat on your turn, target creature you control has base power and toughness 5/5 until end of turn.

When Belief in the World enters, you may tap two untapped creatures you control. If you do or you control two or more Spirits, search your library for a Spirit card, reveal it, put it into your hand, then shuffle.
Creatures you control get +1/+1.

Creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, Bellowing Thoctar gets +2/+2 until end of turn.

Choose target creature with the greatest power or tied for the greatest power, then destroy all other creatures.

Aetherize each permanent you control. Exile Beneath the Horizon. (To aetherize a permanent, create a token that's a copy of it, then exile that token.)

Flying
When Benevolent Malach enters, create a 1/1 colorless Construct artifact creature token.
Sacrifice Benevolent Malach: Artifacts you control gain indestructible until end of turn.

Whenever Beragnian Brawlmaster or another Warrior you control enters, that Warrior fights target creature an opponent controls.
{R}{W}: Target Warrior creature gets +1/+1 until end of turn.

Prevent all combat damage that would be dealt to and dealt by Bereaved Aristocrat.
Unveil {2}{W}{U} ({2}{W}{U}: Transform this. Unveil only as a sorcery.)

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.

You may have Better Half enter as a copy of any creature on the battlefield, except it's a Reflection in addition to its other creature types and it has distorted. (It can be blocked by tapped creatures but not untapped creatures.)

Exile target nonland permanent. Its controller gains 5 life.

Creatures you control get +1/+1 until end of turn.
Artifact creatures and Elementals you control get +1/+1 until end of turn.

When Beyond the Boneyard enters, exile another target nonland permanent until Beyond the Boneyard leaves the battlefield.
Your opponents can't cast spells that share a card type with the exiled card during postcombat main phases.

When Beyond the Veil enters, another target nonland permanent phases out. (Treat it and anything attached to it as though they don't exist.)
Permanents you don't control with mana value 3 or less can't phase in.

Menagerie — This spell costs {2} less to cast if there are five or more creature types among creatures you control.
Destroy target creature with power or toughness 4 or greater.

(Add a quest counter as this enters. Sacrifice after 4.)
Whenever a creature you control enters, add a quest counter.
Exile target nonland permanent an opponent controls until target creature you control leaves the battlefield.
Each player may scry 1.
Put all cards exiled with Bind the Great Evil into their owners' graveyards.

When Bind the Mind enters, each poisoned opponent reveals their hand. Then choose a nonland card name.
Spells with the chosen name can't be cast.