One way to go about deckbuilding in the brand new Pioneer format is to see if we can port over any archetypes that have had any success in Modern. Mono Red Prowess is a deck that has been around a bit, and the key Prowess creatures that we want to build aroundare all legal in Pioneer.
Monastery Swiftspear, Soul-Scar Mage, and Blistercoil Weird are all essentially the same card in this deck. Our goal is to cast several of these cheap creatures on the first two turns, and then cast a flurry of spells to potentially kill our opponent as early as turn 3.
Mono Red Prowess Decklist (Pioneer)
4 Monastery Swiftspear 4 Soul-Scar Mage 4 Blistercoil Weird 4 Runaway Steam-Kin 4 Finale of Promise 4 Warlord's Fury 4 Crash Through 2 Magmatic Insight 4 Expedite 4 Wild Slash 2 Shock 16 Mountain (343) 4 Ramunap Ruins 1 Searing Blood 1 Smash to Smithereens 1 Chandra's Defeat 1 Claim the Firstborn 1 Fiery Impulse 1 Rending Volley 1 Vandalblast 1 Skullcrack
Finale of Promise is a great way to cast three spells from a single card. Every instant and sorcery in our deck costs a single mana, so we can always cast this for three mana for maximum value.
When we're already planning to cast so many cheap spells, Runaway Steam-Kin is an easy inclusion that drastically increases our potential nut draw. Every spell we can cast essentially becomes free, letting us chain together as many spells as we can find. It's also just nice as a two-mana 4/4 creature.
The sorcery suite is just here to draw us into more spells to cast. The trample effect on Crash Through is actually quite relevant in letting us get through blockers if we are able to go off. Magmatic Insight is a very powerful card since it helps us dig deeper when we are just drawing a lot of cards, but we can't run too many copies or we'll run into consistency issues. Having a few in the deck lets us recast them with Finale and goes a long way towards preventing mana flood in this deck that is mostly cantrips.
Expedite is a great instant for us to have access to, as we will frequently want to cast a prowess creature and attack with it immediately. Having a 1-mana cantrip that is an instant is nice to provide more drawing power with Finale. The other slots for 1-mana instant spells should obviously go to red burn spells, though the options in Pioneer are a little bit sad compared to Modern. If Wild Slash and Shock don't do the trick, we could try some more expensive spells that deal more damage. If it turns out that we are facing a creature-heavy metagame, we can also try cards that are a bit more powerful but can't deal damage to our opponent such as Fiery Impulse. However, we don't want to include too many cards that are awkward to cast against an unknown opponent, since we need to be casting our spells to make our creatures punch harder.
Light up the Stage and Skewer the Critics are very powerful red cards in the format, but they don't fit in well in this build. We're not running anything like Lava Spike, so the ability to achieve Spectacle is at direct odds with our desire to cast our spells before our creatures deal damage.
There are certainly many more cards that exist in the wheelhouse of "casting cheap red spells matters", and we're excited to continue brewing with them! Our next focus in this space will most likely be an Arclight Phoenix version of the above deck.