msem-instigator

Flying
When Azos enters, each opponent reveals their hand. You choose any number of nonland cards in players' hands and/or creatures on the battlefield with total mana value 7 or less. Exile those cards and/or permanents.

Flying
{B/G}, Discard a creature card: Badru, the Skyshadow becomes a copy of the discarded card until end of turn, except he has flying and is 5/5.

{W}{B}{G}, Discard a card named Bahet, God of Destruction: Bahet gains indestructible and becomes a God creature in addition to its other types.
Whenever Bahet enters or attacks, each player chooses a number of lands they control equal to the number of lands controlled by the player who controls the fewest, then sacrifices the rest. Players discard cards and sacrifice non-God creatures the same way.

Defender (This creature can't attack.)
Discard a card: Barge Engulfer can attack as though it didn't have defender until end of turn.

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.

When Batrest's Forgemaster enters, you may search your library for an Equipment card, reveal it, put it into your hand, then shuffle.
Whenever Batrest's Forgemaster attacks, Equipment spells you cast this turn cost {2} less to cast.

Whenever Battle-Scarred Combatant attacks or blocks, put a -1/-1 counter on it.

Flash
Haste
{3}, {T}: Exchange control of two target noncreature spells. Their controllers may choose new targets for the spells.

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

Augmented — When Behavioral Specialist enters, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, create a 1/1 blue Elemental creature token with flying.
Whenever one or more creatures you control deal combat damage to an opponent, you may draw a card. If you do, discard a card.

When Benthic Shipcrasher enters, scry 3.

Trample
Bessie's Crusher has haste as long as you control another Wurm.

Lifelink
Whenever Bjarndyr Sergeant attacks, other creatures you control get +1/+1 and gain lifelink until end of turn.

Trample
Other Bears you control get +2/+2.

Flying, lifelink
Whenever Blackhearted Sphinx attacks, you may pay 3 life. If you do, draw a card.

Reach
When this creature enters, put a -1/-1 counter on a creature you control.

When Blighting Ooze enters, put a -1/-1 counter on each of up to X target creatures.
As long as Blighting Ooze is on the battlefield, it has all activated abilities of each creature with a -1/-1 counter on it.

Flying, menace
Sacrifice a creature: Put two +1/+1 counters on Bloodclaw Demon. It gains indestructible until end of turn.

This spell costs {1} less to cast for each creature that attacked this turn.

Wither (This deals damage to creatures in the form of -1/-1 counters.)
When you unveil Bramble Quickling, you may have it fight target creature.

Double strike
{1}{R}{W}: Target creature gains double strike until end of turn. Activate only if Bravery is in your graveyard.

{1}{G}: Target land you control becomes a 3/3 green Elemental creature until end of turn.
{1}{U}: Target enchantment you control becomes a 2/2 blue Nymph creature with flying until end of turn.

When Bridled Narwhal enters, you gain 5 life.

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.

{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.)