This deck finished up the job on getting me to Masters going 7-2. I do not think this list is totally tuned, but I do think it has plenty of potential and is strong as is. I'll go card by card reasoning my inclusions, noting weak points. The goal is to set up a decent early~ early-mid game, hitting fast and hard both on the ground and in the air. Our charge units, Jekk, and burn (whether on units or spells) gives us the reach to close out games once we run out of gas or our opponent manages to wall us (not easy to do).
Eager Deputy - This card has gotta be my favorite common from the new set. A 1 drop that fixes your hand a bit, while gradually becoming a reasonable attacker is quite good. The 2 toughness stops a decent amount of incidental removal. All around good card.
Removal Suite - All of our removal is low costed. Picking off small threats to push damage through or just keeping the board clean early so we can set up meaningful threats that threaten high damage. Annihilate seems to be pretty great right now, mono decks are running around all over the place. Keep in mind that they will be playing Prism which blanks it, but that at least falls to Defile. Defile cleans up early threats. Sear does the same while providing additional reach. I find that I sometimes want more removal, but the consistency is otherwise quite nice. Perhaps removing a few Sears or other Units for Open Contract would push more damage through on average.
Vara's Favor - There is a very strong argument to run the Etchings or a Market card here at a 4 of, but hitting Power is pretty important here and frankly the rest of the deck runs consistently enough in my experience to forgo Salvo or Condemn. People seem to be packing creatures with bigger toughness nowadays anyways, likely in response to Jekk and the popularity of incidental 1 damage effects. Nonetheless I imagine it's probably correct to run some amount of Etchings or Burn Market cards.
Spiritweaver - A really sweet card that fixes our hand while setting up a stopgap to our more impactful turns. Her ability doesn't need to be overwhelmingly catered to to be good. I've found that sometimes even just 1 hit from 1 of our larger units can give us the extra turn in order to win the game. Sometimes she just goes nuts though and essentially puts the game out of reach for the opponent.
Champion of Chaos - Champion of Chaos is back!... and she's a little hard to turn on with these new power bases (no Cylix for us). Through Vara's Favor and a set of 8 plunder units though, we can get there and boy does she still hurt. Fully powered up she gain Lifesteal alongside Spiritweaver which is fantastic. Overwhelm and Deathtouch is still a good combination of abilities and Champion gets to swing into virtually anything.
Jekk, Mercenary Hunter - This is a deck with red in it so we run Jekk. Worth noting Vara's Favor and the 8 plunder units make it really easy to find Jekk fuel.
Milos, Rebel Bomber - Milos feels a little weaker than he did last set, and I think that's directly related to people playing fatter units. Nonetheless, Milos gets across the line to the face often enough that I've never seriously considered removing him from the deck. He's quick and while you can mostly ignore the Firebomb flavor text, don't be too surprised when you win a game because of it.
Buhton, Death's Reach - The reason to be trying out Stonescar, this card can sometimes be a pain to cast but hits incredibly hard. Your plunder units can usually get you to 4 fire influence reliably, and Buhton does not have to come down on 4 to be great. Getting the kill off with his ability can be tricky but is not usually necessary. If it does work, congrats, there is a strong chance your opponent is about to concede. If not, you have a huge creature swinging in that must be answered. Worth noting that with Spiritweaver on the field, Buhton can also perform absurd comebacks.
Impending Doom - Perhaps your main beater, this solid card pops up in decks all the time. With Spiritweaver synergy there was no way this was not being included. An alternate way to get through unit damage when the ground is too mucked up, Impending Doom puts opponents on a very real clock.
Silverblade Menace - This card is okay but unfortunately seemed to be under-performing. In theory it's just what you want, some extra reach and a unit that can get in for some evasive damage. What I found happening more often than not is it gumming up my hand with other more enticing 4 drops. At 2 it seems reasonable to keep them included as I feel that maybe I just kept getting them in worst-case scenarios. No Spiritweaver synergy but a draining flier in the air seems too good a fit in the deck to completely ignore.
Feartracker - This card is just sick in the deck and does what you want Silverblade to do more reliably, twice. If you manage to swing in profitably with Spiritweaver on the field, it can be so hard for your opponent to come back. It is hard to overstate how great the Lifegain in the deck works with helping to push units and finish off games.
Karvet, Redeemed - Just a few copies of Karvet rounds out the air unit. An easy to cast behemoth, Karvet, like most creatures in the deck, demand an answer and tussles with virtually everything in the sky. Notably provides the highest Attack value for Buhton to utilize, taking out popular threats including Icaria.
Powerbase - With no Cylix we make do with Vows and Seats. Not ideal, but with plenty of plunder our base is more than solid and we should have very little trouble casting our cards.
If you make any changes and have success please share! I don't think this deck is fully tuned, just strong.