msem-instigator

Exile target nonland card with mana value 2 or less from your graveyard. Copy it. You may cast the copy without paying its mana cost.
Exile Breach the Lilies.

Put a number of +1/+1 counters on target creature you control equal to that creature's power.
Spell mastery — If there are two or more instant or sorcery cards in your graveyard, you may have that creature fight another target creature. (Each deals damage equal to its power to the other.)

Rouse 2. Target permanent gains trample until end of turn if it's a creature. (Distribute two +1/+1 counters among permanents you control. If they aren't creatures, tap them and they become 0/0 creatures in addition to their other types.)

Trample
Whenever Breaker of Cities deals combat damage to a player, create a 1/1 white Soldier creature token with vigilance.
Crew 1 (Tap any number of creatures you control with total power 1 or greater: This Vehicle becomes an artifact creature until end of turn.)

Until end of turn, target creature gets +2/+2 and gains trample and “Whenever this creature deals combat damage to a player, investigate.” (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Whenever Breakneck Barque becomes blocked by a creature, Breakneck Barque deals 3 damage to that creature.
Crew 3 (Tap any number of creatures you control with total power 3 or greater: This Vehicle becomes an artifact creature until end of turn.)

Exile target artifact or enchantment.

Breath of Hao'Tai deals 4 damage to any target.

{T}: Add {C}.
{1}, {T}: Add one mana of any color. When that mana is spent to cast an Adventure spell, scry 1.

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

{T}: Add one mana of any color. Spend this mana only to cast an instant or sorcery spell.

When Briarform Apothecary enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
Sacrifice a token: Briarform Apothecary gets +2/+2 until end of turn.

Hexproof
Whenever attackers are declared, the active player may pay {2} for each creature attacking you. Then you may have Bridge Kalak become an X/X Troll creature until end of turn, where X is the number of times that player didn't pay mana this way.

{T}: Add {C}.
{1}, {T}: Add one mana of any color. This ability costs {1} less to activate if you control three or more basic lands.

This spell costs {2} less to cast if you control a transformed permanent.
Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Deathtouch
When Brig of the Damned enters, return target creature card from your graveyard to your hand. If that card's mana value is 2, you may return it to the battlefield instead.
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)

Flying, haste
At the beginning of the end step, sacrifice Brightflame Phoenix.
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

{T}: Add {C}.
{1}, {T}: Add {R}{G}.

Brilliant Runepearl enters tapped.
Whenever you cast a permanent spell, you gain 1 life.
{T}: Add one mana of any color. Spend this mana only to cast permanent spells.

Equipped creature has indestructible as long as it's your turn.
Whenever equipped creature attacks, it gets +X/+0 until end of turn, where X is its power.
Equip {6}

{2}{R}: Target creature can't block Brimstone Courser this turn.
Ride {3}{R}{R} ({3}{R}{R}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

{T}: Brimstone Grenadiers deals 1 damage to target player.
Whenever you cast an instant or sorcery spell, untap Brimstone Grenadiers.

Foretell {1}{R} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)
Brimstone Oration deals 2 damage to any target. If this spell was foretold, it deals 4 damage to any target instead.

{T}: Add {C}.
Crew 3 (Tap any number of creatures you control with total power 3 or greater: This Vehicle becomes an artifact creature until end of turn.)

Destroy target creature with flying.
Draw a card.