msem-instigator

Haste
Bloodvenge Berserker doesn't untap during its controller's untap step.
Once each turn, when an opponent is dealt damage by another source you control, you may untap Bloodvenge Berserker.

Menace
Revive {1}{R} ({1}{R}, Exile this card from your graveyard: Create a token that's a copy of this card, except it has no mana cost. Activate this ability only any time you could cast a sorcery.)

Target creature you control gets +2/+2 and gains hexproof until end of turn.

Prevent all combat damage that would be dealt to and dealt by creatures this turn.

Target creature gets +2/+2 until end of turn.
Fuse (You may cast one or both halves of this card from your hand.)

When target creature dies this turn, return it to the battlefield under its owner's control. When you do, germinate. (Put a +1/+1 counter on a creature or create a 1/1 green Saproling creature token.)

Target creature and all other creatures with the same name as that creature get +2/+0 until end of turn.

Target creature gains indestructible until end of turn.

As an additional cost to cast this spell, sacrifice a creature.
Destroy target creature.

Whenever another creature you control dies, you may pay {1}. If you do, scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Sacrifice Bonetooth Darter: Counter target instant, planeswalker, or sorcery spell unless its controller pays {1}.

If casting this spell causes a triggered ability of its target to trigger, that ability triggers an additional time.
Target creature gains first strike until end of turn.

Menace (This creature can't be blocked except by two or more creatures.)
Assault {R} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)

{1}, Sacrifice Brackwater Scuttler: Draw a card.

{1}{B}: Regenerate Brainless Ghoul. (The next time this creature would be destroyed this turn, it isn't. Instead tap it, remove all damage from it, and remove it from combat.)

Enchant creature
When Bramble Armor enters, put a +1/+1 counter on enchanted creature.
{G}, Sacrifice Bramble Armor: Enchanted creature gains indestructible end of turn. Tap it.

{5}: Brass Dragon gets +3/+0 and gains flying and first strike until end of turn.

Enchant creature
Enchanted creature gets +2/+2 as long as it's an Actor. Otherwise, it gets -2/-2.

Flying

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.

Broken Deathbringer gets +1/+0 as long as you have 10 or less life.
Broken Deathbringer gets +1/+0 as long as there are one or fewer cards in your hand.

Target creature gets +0/+3 until end of turn. Whenever that creature perseveres this turn, draw a card. (A creature perseveres when it survives damage.)

Whenever a creature you control becomes the target of a spell or ability, counter it unless its controller pays {1}. Whenever they do, put a +1/+1 counter on Brushcover Elf. (This includes your spells and abilities.)

Destroy target artifact.
Reprise {R} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Target creature gets +3/+3 until end of turn.