Argunport

Argenport Gunslingers, my first public list, and the first list to get me into Masters.

The basic idea is to build upon the already proven interaction of Bartholo, the Seducer with the Lifesteal-giving Lethrai Falchion and Bloodletter by bringing in Stella, the Shotcaller as an additional Aegis threat that can also buff up the entire deck if she's holding a weapon.

Card Choice
Protect: The deck plays a fair bit on the Voltron side of things, stacking up weapons and units in a package that could all die to well-targeted removal. The second or third Aegis is good for the same reason the first one was.
Argenport Instigator: a 3/3 for 2 hasn't suddenly stopped being good with set 3, and this guy gets even better Simply by virtue of being a Gunslinger!
Auric Vigilante: Not my favorite card in the deck, but an important roleplayer. It grows every time it attacks, so play early, swing often. Once it dies,it comes back to do it again. - Problems: Weak to Vara's choice and early blockers with more than 2 toughness.
Hideout Pistol: A removal spell and a way to turn on Stella in one card? Sign me up!
Rapid Shot:This card has 2 modes, Win creature combat, and Win the game. Sure there's no overwhelm here for it to combo with, but being able to add massive burst from an unblocked unit, especially when combined with Showdown makes it worth the slot.
Bloodletter: What can I say? this card is super pushed. The stats are great for a 3-cost weapon, Lifesteal often is an on-the-spot victory against all-in aggro that lacks sustain, and still incredibly powerful when your opponent decides to race because they aren't exactly going to be blocking Bart.
Cabal Countess: Another creature I don't love, but still continues to pull it's weight. Her statline is good for picking off larger threats with Hideout Pistol and attacking into an empty board or after she ults. Ambush on her is best against Control decks that aren't running Fast Killspells. The kind of deck that often leaves openings for her to get in there. She and Auric Vigilante would prove quite poor if skycrag with Rockslide becomes a significant part of the metagame.
Showdown: Like Rapid Shot but better! Showdown often shows the other guy the door, and then goes the extra mile to kick them through it. As long as you have a creature, showdown can save it from damage, be it combat or burn. Unlike it's cheaper shadowy brethren, showdown can save a blocker's life too. If your opponent doesn't block gratuitously at all times, this card can end the game out of nowhere.
Slay: It's hard removal, next.
Stella, the Shotcaller: My waifu. She does a Stellar Bartholo impression from back when he cost 3, and on top of that she makes everything in the deck bigger if she's holding something! She snowballs, and does it fast. One trigger is a powerful buff to your upcoming draws, two triggers are often enough to win the game. Like I said for Protect, Aegis is really good. If she didn't exist, I wouldn't be playing this deck.
Auric Runehammer: There's not much I can say about this card that hasn't already been said. It's very pushed removal that doubles as pressure. It does die to Nightfall and your own Instigator triggers, which is important to be careful of, but it's still too strong to even consider cutting. Bart can also go grab it if you get to 7 power.
Bartholo, the Seducer: Anyone who was playing Eternal when the Tale of Horus Traver released remembers the dark days of Tavrod, Auric Broker, but they were as much facilitated by this guy as by the cows themselves. So much so that Bart got Nerfed from costing 3 to costing 4. Well, it turns out he's still strong now that being a Gunslinger is so relevant. Slap some sword, guns, hammers or chainhooks on our pretty boy and get in there. (Aegis is still good)
Hammer of Might: As close to Bart as Stella is, she doesn't actually have unblockable. This means toughness on weapons is valuable for her. I've still not decided on what the Hammer/Falchion split should be for this deck.
Lethrai Falchion: Lifesteal and a bunch of power are still good buffs, especially on bart! one hit alone is a massive life swing that is often tough for your opponent to come back from. Once again, I've not yet come to a conclusion on it vs Hammer.
Shadow Sigil: Decks need power, I included this because I didn't want to feel lonely as the only card I didn't talk about.
Amethyst Waystone: Running out of threats sucks, card draw helps you avoid that. Even though Nightfall is a symmetrical effect that your opponent gets the bonus from first, It's totally fine in almost every situation. Unless you are already putting pressure on an enemy who's run out of answers, you want this effect. That said, I can't imagine it being correct to skip an important power drop to sandbag for the card draw.
Common Cause: An always-undepleted power source that's Justice when you need it to be, Shadow when you need it to be, and factionless when you aren't in need of influence. This card is like Diplomatic Seal because it fixes your influence early, but it also works if you're influence screwed and have two of your creatures stuck in your hand.
Crest of Vengeance: This cycle might actually just be the most powerful cards in the set. People who are worried about it being depleted are grossly underestimating it. Eternal's power system makes a depleted source when you're influence screwed totally fine, and since this deck isn't playing any one drops, you aren't missing anything on the first turn. The scry-er, I mean scout is almost as good as an additional draw, and is actually just so free on a power card.
Diplomatic Seal:A 2 faction deck running Diplomatic Seal? Shocking! Seal remains fantastic fixing for a deck with a total influence requirement of SSJJ.
Emerald Monument: Yes, it's depleted power. 7 sources being slow isn't enough to be a problem for this deck, and it being a real card once you're late enough in the game to play anything else in your deck is huge for smoothing out your draws.
Emerald Waystone: The bonus is small, but the cost is nonexistant. Remember if you plan to bulk up an Auric Runehammer with this you can lose that armor to it's Amethyst counterpart or an Argenport Instigator.

Thanks for your time reading this, I hope it was helpful! Don't be afraid to ask questions or offer suggestions!

Edit 1: 12/20/17
Out: 4 Seek Power, 4 Annihilate, 4 Inspire, 3 Justice Sigil, 1 Shadow Sigil, 4 Seat of Vengance
In: 3 Protect, 4 Auric Vigilante(up from 2,) 4 Hideout Pistol(up from 3,)4 Rapid Shot (up from 3,) 4 Cabal Countess(up from 2,) 4 Slay(up from 3) 2 Hammer of Might, 3 Emerald Waystone, 4 Amethyst Waystone (up from 3.) 4 Common Cause

Reasoning:
Generally, I brought a lot of numbers up to 4 for more consistency with the cards I determined I really want.
Cuts
Seek Power: No real logic behind pulling this, it may be straight up wrong. I'd like to know more about what decks want it and why.
Annihilate: Felt like it spent way too much time dead for me to actually want to play it. Hideout Pistol and Slay really feel like all the removal I really want.
Inspire:Too slow for not enough payoff. This deck wants to be aggressive and spending a turn, as was often the case, to draw one card really isn't helping that plan.
Justice Sigil&Shadow Sigil In removing the seek powers, I freed myself up to play as many waystones as I could fit. Without anything searching my deck for sigils, waystones are objectively better.
Seat of VenganceThe other card that gets so much worse without sigils. The power base is better off with out it. It was holding us back!
Additions (only the new stuff)
Protect: This deck builds up on singular units, and even though Stella, the Shotcaller and Bartholo, the Seducer come pre-loaded with an Aegis, you often want another.
Hammer of Might: Since Stella doesn't have Unblockable, she sometimes finds herself in situations where she'd be throwing her life away to attack. Hammer does a better job than Lethrai Falchion at helping her get through 3 or 4 power of blockers while living to buff up your deck again. The additional Warcy 3 offsets the cost of not giving Lifesteal, but I'm not sure yet if it's enough to make go 4 Hammer, 0 Falchion.
Emerald Waystone: Without seek power, It's actually strictly better than a sigil.
Common Cause: Doesn't always get you an influence, but d it's more likely to when you need it to. It's also undepleted. Always.

I may do a writeup on other cards I've considered and/or possible sideboard cards at some point.