I’ll contribute since this seems to be the Songhai thread 
Mask Backstab Kaleos:

So I haven’t gotten to test this much (I’ve tested the deck below much more), but I’m pretty sure Backstab Kaleos is a thing now. While this archetype still probably gets blown out by the same things that blew it out before (namely, Magmar), it can highroll a lot harder now with these new 4 drops.
Some opinions on cards:
Bakezori
This thing is really, really good for Backstab decks particularly. Why? It’s stupid good card draw. It draws more cards than Spelljammer, it doesn’t draw those cards for your opponent, and it’s really hard to get rid of if you do the perfect P1 T1 Scroll Bandit/Kaido Assassin into P2 Bakezori + Jux + Kill opponent’s thing. Even without that, it’s 6 HP, and you can just get instant value if you wanted to with Kaleos BBS. It cantrips movement spells. It’s amazing.
Massacre Artist
Honestly, I thought this card was meh when I saw it. But it’s actually pretty good too. Again, 5 HP breakpoint is a big deal. The effect does not require a board to make use of either. Getting a free attack with your general is perfectly acceptable. Moreover, it combos really well with the new artifact since you’ll preserve durability.
Horned Mask
Again, at first glance I didn’t think this would be good. Then I read my good man @owlbeastmd 's post and realized the potential to punish wallhuggers with Cyclone Mask. Which, Cyclone Mask hasn’t been that great (maybe because I haven’t found any wallhuggers), but Horned Mask has proved to be really quite good because Bakezori covers its weakness (namely, running out of cards). Provides solid tempo and makes your little 2 drops into bigger and bigger threats.
Kaido Expert
Haven’t tried this card at all yet. I’ve only seen it in hand once, but I’d guess it’s probably not good. I can maybe see it with Horned Mask buffing it to a 3/3, but eh. More experimenting needed.
Jungle Kaleos:

Now this is my deck. I can’t get a gauge on how good it actually is (early in the expac and aggro is naturally going to be a bit stronger), but boy if it doesn’t seem solid. The strength of this deck is its sheer uninteractivity. Early game you typically aim to chip your opponent down to 16-18 HP, then it’s all over. This deck has several late game burst combos that also leave behind big bodies. This is important because it lets you just go face and tells your opponent, “deal with it.” You get the flexibility of combos combined with just having solid standalone cards. Though, I am on edge about the…
Knucklestorm
I don’t really want this card, but at the same time I don’t know what’s better. It’s actually been pretty okay because of it’s flexibility as a ping or as face damage. It’s important that every card (or almost every card) in this deck is able to go face, so something like Gotatsu isn’t a viable replacement. Overall I’m surprised by the quality of this card (in this deck), but it still feels like something better suited to a combo deck.
Phoenix Barrage
So I really like this card. Like I noted above, it’s an integral part to the whole uninteractivity of this deck. The best way I can put it is that it’s a cheaper, more flexible spiral technique. You basically just play this to do damage and get more damage for later turns. Or you can do the 6 damage on 7 mana. Or you can replace the PF for another card. The important factor is that this is one card instead of requiring a huge combo to get the damage and utility.
Coalfist
Good card. Great card, even. It’s playable on the first one, and gets nuts on subsequent plays. You’ve gotta understand that +4 ATK and a 4/4 for 4 mana is really nice. This combos well with Tusk Boar. It’s 4 damage + a 4/4 for 6 mana, then 6 damage + a 4/4 for 6 mana, then 8 damage + a 4/4 for 6 mana. The latter two are good for pushing damage or closing out games. It’s also just more damage, so you can never go wrong there.
SABERSPINE ALPHA
The cornerstone of this deck. It’s a 7 mana 5/5 with rush, what more can you say. Good late-game aggro bomb to go face or clear board. Almost always leaves behind a body that your opponent must deal with. It alleviates an issue with Songhai aggro, which is the constant need for combos to actually deal your damage. This just lets you say, “whoops, I topdecked 5 damage, now you’re dead.”
Overall I’m liking this second deck a lot. I’m curious to see how it performs after the meta settles down, but it’s been treating me well so far.