msem-instigator

Flying, menace, haste
When Bloodfiend Ravager enters, it deals 2 damage to any target. If a permanent dealt damage this way would die this turn, exile it instead.
Evoke {1}{R} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Flash (You may cast this spell any time you could cast an instant.)
When Bloodhunter Orca enters, target opponent sacrifices a creature that was dealt damage this turn.

Bloodline Zealot gets +2/+0 and has menace as long as you've sacrificed a permanent this turn.

Frenzy 1 (Whenever this creature attacks and isn't blocked, it gets +1/+0 until end of turn.)

When Bloodpact Collector enters, destroy target creature an opponent controls that was dealt damage this turn or has a -1/-1 counter on it.

When Bloodpact Tormentor enters, you may put a -1/-1 counter on target creature.
Bloodpact Tormentor can't be blocked by creatures with counters on them.

Enchant land
Enchanted land has “{T}: Each opponent loses 2 life.”

Flash
This spell costs {2} less to cast if five or more cards are in your graveyard.

Bogchomper Juggernaut attacks each combat if able.
Bogchomper Juggernaut can't be blocked by Fungus, Saprolings, Plants, or Insects.

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

Haste
Augmented — Whenever you cast a spell, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on Bolstered Guardian. It loses this ability and gains “Whenever this attacks, it deals 2 damage to each of up to two targets.”

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

Trample
{1}{G}: Brackish Kelpie gets +2/+2 until end of turn. Activate only once each turn.

Target opponent discards two cards. (Cast a copy of this spell once while this creature is on the battlefield.)

Gain control of target permanent. (Cast a copy of this spell once while this creature is on the battlefield.)

When Brand New Species enters, create a tapped 3/2 green Horror creature token.
Augmented — At the beginning of each end step, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on up to one target Horror you control.

You may put a permanent card from your hand onto the battlefield. If it's a planeswalker, it enters with five loyalty counters rather than any other amount, and you may activate its loyalty abilities this turn any time you could cast an instant.

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

Exile target creature. You gain 2 life.

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.

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.

{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.)

Trample
When Bringer of Armies enters, recruit. (Create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)

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

At the beginning of your upkeep, you may discard a land card. When you do, create a 2/2 green Wolf creature token.