Interesting tight build. The power of Labyrinth Raptor is evident.

I like some one mana burn like Play with Fire or the above mentioned Spikefield Hazard  ^Flip but the synergy with cheap burn and your Pestilent Spirit can be overwhelming.

One potential addition could be Insolent Neonate this could keep in theme but also dig you through your deck.

Finally Rampaging Ferocidon is just a powerful creature with menace.

@ enraged

Hey, glad you liked the build. It's quite a fun one to play.

On your suggestions, I've already looked over every single 1-mana burn spell legal in the format and End the Festivities, Blazing Volley, and Dual Shot are unquestionably the best options to pair with Pestilent Spirit (In that order, too). If I need Instant speed, I don't see a value in Spikefield Hazard when I could just as easily Dual Shot. Mana isn't even close to a struggle in this build as it's all quite low cost, and I already have 4x Goldhound in there just in case things get really dire, so I don't ever see the Land side being used either.

The Neonate isn't bad at all, but I don't know what I'd drop to put her in honestly. My other 1-drop Menace creatures all have pretty well-definited versatility within the build (Goldhounds for mana, Valentin for converting destruction to exile), compared to Card Draw - which while nice - is nowhere near as predictable a benefit overall.

Lastly, I toyed with Rampaging Ferocidon for a while when I first built the deck, but anymore he's just not anywhere near as threatening as other 3-drop creatures. I ended up with Pestilent Spirit as my 3-drop, but I used to run Sonorous Howlbonder, who for all intents and purposes makes large chunks of my deck simply unblockable. So, that's the standard I'm comparing against currently for 3-drops. Figure in the fact that the Ferocidon punishes Creature spells (and I run mostly Creatures myself) and this feels like it'd just be working against my own Lifelink most of the time. I can fill the same overall function with Knight of Dusk's Shadow now; for less mana, and no downsides to me.

I do appreciate the interest and suggestions though, and I'd be happy to hear if you have some additional thoughts that maybe I've overlooked.

Either way, Cheers!