msem-instigator

Whenever Bourasan Street Watch attacks, you may pay {W}. If you do, Bourasan Street Watch gains indestructible until end of turn.

As Brave the Issbarrens enters, choose a color.
White creatures you control have protection from the chosen color. (This permanent can't be targeted, dealt damage, enchanted, or equipped by anything with that color.)

Destroy target artifact or tapped creature.

Double your life total. (Then exile this card. You may cast the creature later from exile.)

Exile target creature. You gain 2 life.

Improve {1} ({1}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
When Bridgehaven's Finest enters, create a 1/1 colorless Human creature token.
Other creatures you control get +1/+1 as long as Bridgehaven's Finest has two or more counters on it.

When Bridled Narwhal enters, you gain 5 life.

Lifelink
When Bright-Eyed Adventurer enters, rediscover an enchantment card. (Look at the top card of your library. You may reveal it and put it into your hand if it's an enchantment card. Otherwise, put it back or into your graveyard.)

Spells cost {1} more to cast for each colored mana symbol in their mana cost beyond the first. (For example, a spell with mana cost {W}{W} would cost {1}{W}{W} to cast.)

Flying
When Brilliant Griffin enters, target creature gets +2/+2 until end of turn.

Choose one —
• Brimstone Cleansing deals 4 damage to target tapped creature.
• Exile target enchantment.

Defender
When Brine Duelist enters, create a Treasure token. (It's an artifact with “{T}, Sacrifice this permanent: Add one mana of any color.”)
{W}{U}{B}{R}{G}: Put a +1/+1 counter on Brine Duelist. It loses defender.

Flying, vigilance
Protection from Humans (This creature can't be blocked, targeted or dealt damage by Humans.)

Whenever Bristled Wolverine attacks, it gets +1/+1 until end of turn.

Bristling Skoki has first strike as long as it's attacking.
Whenever Bristling Skoki blocks a creature, you may have it deal damage equal to its toughness to that creature.

Distribute three +1/+1 counters among up to three target creatures you control. Those creatures gain first strike until end of turn.

When Broken Spirit enters, exile target creature an opponent controls until Broken Spirit leaves the battlefield.
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.)

Concord — Whenever Bubbledome Captain attacks, if there are four or more card types among permanents you control, each other attacking creature gets +1/+1 until end of turn.

Untapped creatures you control get +0/+2.

Target creature gets +2/+2 until end of turn. If it's an artifact creature, it gains indestructible until end of turn.

Players can't untap more than three permanents during their untap steps.

Exile target artifact or enchantment with mana value 4 or less.

Creatures you control get +0/+1 and can attack as though they didn't have defender.
Whenever three or more creatures you control attack or block, each creature you control assigns combat damage equal to its toughness rather than its power this turn.

Flying
When Byte Bug enters, conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

Flying
When Cadre Hawk enters, you may search your library and/or graveyard for a card named Cadre Hawk, reveal it, and put it into your hand. If you searched a library this way, shuffle.