msem-instigator

Whenever you cast a noncreature spell, Architect of Calamity deals 2 damage to each opponent.

Aspiring Dragon has flying and haste as long as you control another Dragon.
{2}{R}{R}: Aspiring Dragon gets +3/+0 until end of turn.

Sacrifice a creature: Exile the top card of your library. Until end of turn, you may play that card.

Battalion — Whenever Barbarian Rager and at least two other creatures attack, Barbarian Rager gets +2/+0 until end of turn.

Armed — Beragnian Savage gets +1/+0 and has first strike as long as it's equipped.

Menace
When Bit Player dies, it deals 1 damage to each opponent.

Double strike
Attain {3}{R} ({3}{R}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

Advance {1}{R} (Cast this for {1}{R} to advance it as it enters. {1}{R}: Advance this as a sorcery.)
Whenever Blitz Breaker advances, its power becomes equal to the amount of noncombat damage that's been dealt to your opponents this turn. (This effect lasts indefinitely.)

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Bloodied Twinblade dies, scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)

Whenever Bloodthirsty Insurgent attacks, it gets +2/+0 until end of turn.

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.)

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.)

When Broadside Raider enters, create a 1/1 blue and red Pirate creature token with haste.

Menace, haste
Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)

First strike
Whenever you make first contact, Callous Conduit deals 1 damage to target player or planeswalker. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)

Haste
Whenever Carnival Daredevil deals combat damage to a player, exile the top card of your library.
Duet — You may play cards exiled with Carnival Daredevil as long as you control exactly two tapped creatures.

Haste
Caulte Axeslinger gets +2/+2 as long as any opponent lost exactly 3 life this turn.

Sacrifice Chromeleon: Add one mana of any color. Scry 1.

{1}{R}: Circus Firebreather gets +1/+0 until end of turn.

Haste
This creature can't block.
{2}{R}: Return this card from your graveyard to your hand.

Whenever you draw your second card each turn, put a +1/+1 counter on Current Surfer.
{R}, Discard your hand, Sacrifice Current Surfer: Draw X cards, where X is its power. At the beginning of the next end step, discard your hand.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Cycling {2} ({2}, Discard this card: Draw a card.)

Whenever you cast a spell, Daughter of Suisei deals 2 damage to target opponent if that spell has the same name as a card in your graveyard.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever a player activates an ability of an artifact, creature, or land, if it isn't a mana ability, Dedicated Weaponsmith deals 2 damage to that player.

When Deputy Gibem enters, post a bounty on each creature and each planeswalker. (Put a bounty counter on those permanents. Each of them have “When this permanent dies, each opponent draws a card” as long as it has a bounty counter on it.)