msem-instigator

Whenever Baljurn, the Runelord or another nontoken artifact or enchantment you control enters, create a 0/0 blue Construct artifact creature token. Put a +1/+1 counter on each artifact and/or enchantment creature you control other than Baljurn.

Vigilance
Whenever Bartimus attacks, another target attacking creature gets +1/+1 until end of turn. If that creature is a Soldier, put a +1/+1 counter on it instead.

Flash
Once each turn, you may cast a spell without paying its mana cost. If you do, at the beginning of your next upkeep, you lose the game unless you pay that spell's mana cost.

Protection from multicolored
[+2]: Create a colorless artifact token named Mind Stone with “{T}: Add {C}” and “{1}, {T}, Sacrifice Mind Stone: Draw a card.”
[–3]: Create Barxbot 9000, a legendary 6/4 colorless Construct artifact creature token with “All damage that would be dealt to Barx planeswalkers you control is dealt to this creature instead.”
[–12]: You and target opponent each gain control of each permanent the other controls that's one or more colors.

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.

Batrest, Fellor Leader gets +1/+1 for each Equipment attached to it.
When Batrest enters, create Astrina, Forged for Glory, a legendary colorless Equipment artifact token with “Equipped creature gets +4/+4 and has first strike and lifelink” and equip {4}. Attach it to Batrest.

Menace
When Beatrice enters, target opponent reveals their hand. Exile a nonland card from it. During any turn that player lost life, you may cast that card and mana of any type can be spent to cast that spell.

Whenever you cast a noncreature spell, Pirates and Rogues you control get +1/+0 and gain trample until end of turn.
Whenever this creature deals combat damage to a player, you may sacrifice it. If you do, return target instant or sorcery card from your graveyard to your hand.

Flying
Belmord can't block.
{1}{B}: Create a 1/1 black Bat creature token with flying and “This creature can't block.” Activate only if a player gained or lost life this turn and only once each turn.

[+1]: Creatures you control get +1/+0 and gain haste until end of turn.
[0]: Bennett Brooks deals 2 damage to each opponent. If you have an insight counter, create two Treasure tokens.
[0]: You get an insight counter.
[–2]: Sacrifice an artifact. If you do, return target artifact card from your graveyard to the battlefield.

Flying
Sacrifice six Swamps: Return Berbarus Unsealed from your graveyard to the battlefield with an indestructible counter on it. You draw six cards and you lose 6 life.

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.

{1}{G}: Until your next turn, Bessie becomes a 5/5 green Wurm creature with trample, haste, and indestructible. You can't activate this ability while Bessie is being attacked. (She doesn't lose loyalty while she's not a planeswalker.)
[+1]: Creatures you control get +1/+1 and gain haste until your next turn.
[–6]: Create five 3/3 green Wurm creature tokens with trample and haste.

[+2]: Create a 3/3 red Wurm creature token.
[–2]: Up to three target creatures each get +2/+2 until end of turn. Bessie deals 2 damage to each of up to three target creatures.
[–9]: You get an emblem with “Creatures you control have base power and toughness 7/7 and have indestructible.”

Trample, haste, indestructible
Whenever a permanent an opponent controls is put into a graveyard from the battlefield, put a +1/+1 counter on target Ooze.

Flying, deathtouch, lifelink
Ride {1}{B} ({1}{B}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)
You may activate Bonescourge Kazadrak's ride ability from your graveyard by sacrificing a creature in addition to paying its other costs.

{R}, {T}, Discard a card: Draw a card.
Whenever one or more cards leave your graveyard, create a Weapon token and attach it to a creature you control. (It's an Equipment artifact token with equip {2} and “Equipped creature gets +1/+1”.)

You may activate Boxue and Ma'Long's loyalty abilities an additional time if you've cast two or more spells this turn.
[+1]: Scry 2.
[–2]: Exile the top two cards of your library. You may play one of them this turn. When you do, put the other card into your hand.
[–6]: Whenever you cast a spell this turn, copy it. You may choose new targets for the copy.

[+2]: Discard a card at random. If you do, draw two cards.
[0]: Target creature's controller may pay X life. If they don't, you lose X life and gain control of it (Choose any number for X.)
[–3]: Flip a coin until you lose a flip or choose to stop flipping. For each flip you won, draw two cards and create a tapped Treasure token.

Whenever you attack or cast a multicolored spell, put a +1/+1 counter on Brandy Axel.
If Brandy Axel would be destroyed, remove a +1/+1 counter from her. If you do, instead remove all damage from her and she deals 2 damage to each opponent.

Flash
Flying
When Branu enters, return up to one other target creature you control to its owner's hand. If you do, create a token that's a copy of that creature, except it's 1/1.

Flying, trample
Whenever Bretala of Redsky attacks, it gains double strike until end of turn unless defending player sacrifices a creature.

If you would draw a card, you may instead choose creature or land and exile cards from the top of your library until you exile a card of the chosen kind. Put that card into your hand and put all other cards exiled this way on the bottom of your library in a random order.

Augmented — Whenever Bril, the Oltenen Emissary enters or attacks, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, destroy target permanent.