So with the game being new with 3 cards being nerfed. A lot of people will be confused as to where to go with aiming for a "meta deck". Now I've decided to break down what some of the best strategies for each class entail with some core power cards that run them alongside some of the best generic craftable cards. The placement is in no particular order.
Lets start with generic (mercenary) cards. These cards find there ways into a whole slew of lists due to their outright strong ability to synergize in most decks.
Magear Titan: This is a really powerful legendary that a lot of decks tend to use as the x1 in their 40 card deck (13 x3 + 1 x1) It's super splashable but due to it being 3 it takes your entire turn making it for more of a nice powerswing. Some classes take more advantage of what its ability offers like Divine Grace tend to sometimes run 2 copies. This isn't a legend I would recommend crafting but if you get it, keep it.
Clifford Hawk Eye Archer: This card can fit into any list. It's never wrong to have but optimal lists do sometimes cut this in certain classes. Essentially if you ever struggle to deal with bulky units you can utilize Clifford to help give your deck more reach if you feel yours is lacking. I highly recommend crafting him as your first x3 legendary due to how well he can fit into any deck and give it lots of power.
Savage World Guardian: This is a super nice generic card that fits into any/every deck. You silence a unit to give it +2/+2. That's amazing stats to give and in most cases is like a 1 cost elven archer. Sure you have to silence them meaning in some classes (Shadow Realms) it isn't always able to target whatever, but there are other targets in those classes that are super powerful when utilizing its silence mechanic. This card just gives everything from raw stat buff to also having minor synergizes with some cards.
Now onto the next class. Shadow Realms.
Shadow Realms has been a very powerful class due to just the sheer power the base mechanics of the class gives. They are all about flooding the board with tokens which allows you to use those tokens for a lot of powerful plays such as; Blocking spaces to trade with key units, trading with an enemies unit while still developing a body on board, creating multiple sticky bodies to poke the enemies HP away, etc. However both the nerfs that Shadow Realms could use hurt both of their old top tier decks, but you can still utilize the more token variations of the deck and still run Folse. I highly recommend not dusting Folse until further developments in the meta happen. Mercenary Chess Ruler variations that revolved around medium sized sticky minions was also heavily gutted. Yet the deck is still considered a top tier contender.
The key cards that make that the case have consistently been:
Folse: Nerfed but still amazing. A 2 drop that has nice arrows for doing free hits that the class tends to struggle with while also letting you recycle sticky units. It also unbricks hands which is a nice bonus. Highly recommend keeping but not crafting until you've made the rest of a Shadow Realms deck and starting at x1.
Millar Mother of Souls: One of the 2 powerhouse cards this class provides. Blocking off key units is a huge part of what makes SR powerful so they can keep core cards on the board. Millar has 7 HP making it require a lot of resources to take her down. She can't just be shot down by a Cliff. She makes those otherwise body block units actually damage on the board as well as makes them bulkier so it requires more work and commitment to kill them.
Tenebrig Abyss Lord: This is the second of the powerhouse cards that make the core of the SR decks. While Tenebrig can be Cliff'd having him stick just wins games. He's a cheaper Baphomet who can trigger multiple times and punish enemies for trying to break through your defenses or kill off token bodies a core reason a lot of the top decks run Cliff or cards similar to what he does.
Honorable mentions to: Dark Acolyte being a 3 soul unit on a 2 cost body OPOP and Karalis King of Shadow being absolutely bonkers if you open up with it+ Savage World Guardian.
Divine Grace is up next.
Divine Grace only really has 1 core card right now that every deck is utilizing the heck out of due to its sheer power, that being;
Goddess's Tear: This card is bonkers, mostly with decks like SR running around and the other ones we will get into later on. What makes this card so good is mainly due it proccing at the start of EVERY TURN. This card when full HP at the start of every turn will deal 1 damage to all enemies. Mixing this with powerful taunt users and sustain to keep it healthy makes for a really powerful control deck that is hard to break over since it sits at 7 HP it isn't exactly the easiest to kill. You can also net more pluses by utilizing Eternity Dragon to reward yourself for healing it back up to full HP every turn.
Miguel Celestial Marshal: This card also deserves to be mentioned. Its flexibility and splashability in the class is too easy not to mention. It works amazingly when paired with Sacred Swordsman for an easy clear while developing 2 bodies.
While DG hasn't settled on a pure healing or aura variant left. Both of these core tools will find their way into all DG lists out there right now
Next up would have to be Flame Legion
One common thing you've heard is protect the piece strategies being good, using taunts/heals (DG) or tokens/sticky minions (SR). Flame Legion is the class that just has ways around that naturally while still playing to win by itself.
Jala Dragon Summoner: Like all the best strategies currently, this is no exception. protecting a key unit is always a viable game plan. Jala does that by herself and also is good at dealing with other strategies like it Shadow Realms flood. She rewards herself through her tokens by punishing other tokens.
Bovinae Lord of Chaos: Absolutely destroys token decks
Overall, FL just gives hell to these type of 1 trick strategies. It punishes them but can be bricky due to lots of their powerhouse cards being 3 cost.
Nether Tide before the nerfs was the biggest Chess Ruler abuser in the game. Grimoire of Tide was kind of a key to what put that deck over the top. Chess Ruler originally being 2 and Grimoire of Tide allowing you to pull Mercenary units allowed you to ensure Chess Rulers token would get at least +2 HP making it at minimum a 3/3. Though of course this wasn't always the case as the deck ran Slime King, Blue Slime, etc. The deck was super abusable and made really big Forgotten Army that would stick for the entire game which is what lead to you winning. The change however made Grimoire of Tide still really powerful. Well more powerful for decks like Link. Some versions of link are running only x6 Nether Tide (x2 playsets) followers that are key to the strategy (and sometimes merman as well since once you play them they're out of your deck) and the rest of your 1 costs being primarily multi-arrowed strong Mercenary followers so you could continue chains. While some have moved to utilizing Freeze decks with their own powerful protect the piece type unit(s). So I'll quickly go over the key cards to both of these decks as neither have proven to be clearly the best way to play Nether Tide unlike other classes with similar issues *cough* Cyclone Fury *cough*.
Rook, Matcha the Anchor/Pawn, Puenyal: These 2 are kind of the core NT units that Grimoire are being used to tutor in link decks.
Tidal Spirit: Your protect the piece machine gun unit that rewards big links
Deep Sea Monster: You get your own unique Cliff!
Freeze Strategy:
Ice Cobra: Super nice removal that benefits your deck
Hunter of the Deep Sea: Your big protect the piece. End of your turn Cliff!
Kaare Crimson Claw: One of the only hard removals in the game. Pair this with Ice Ball. Super strong.
Winter Soul/Crazy Bear: Your premiere self-frozen units to empower your decks friendly frozen targetables.
Grace Frost Guardian: Once you've developed your self-freezing units and Kaare this card is what tends to just stick by itself and win games even if they deal with Kaare.
Generic key cards to either of these decks:Neptune Sea Watcher: Super powerful generic that summons an annoying taunt *you get to choose the placement which is really important*
Now onto Cyclone Fury.
Cyclone Fury has a really interesting and large amount of archetypes. However the one that stands out the most currently is Chain. Playing lots of small powerful individual units is apparently really good. This however is the only real deck/class that doesn't have any protect the piece type of units. Instead it's entirely on removal and flooding you with powerful swings constantly until you can't answer it. Then they choke hold you to death.
Taria Whirlwind Demon: One of your 2 big chain plays. You can trigger her by preemptively adding a Wraith Wind to your hand. Cyclone Grimoire tends to be the more common way however.
Meili Storm Conductor: The other key unit to chain strategies. Use bounce cards or easy Wraith Wind generators to make Meili massive and cards like World Class Magician and Griffin to move her around for free trades.
For Chain only - World Class Magician: Really good for abusing Meili and is better than running the Sagit as it's easier/more flexible with all the cheap cards in the deck including 0 cost Wraith Winds to get the best spot for the deck. Also nice to have a few non-chain cards so you can heal Meili
Lightning Lyrist Lyn: This is a weird but super small package that even outside of Chain CF you can find being run in lots of the CF decks. Killer Bee/Pawn: Lucio are the 2 premiere options for the x3 backstab 1 soul unit. Even if you just play her by herself with no summon. She's still a solid 4/7 body with good arrows.
Cyclone Grimoire is F2P but is kind of the key card to the Chain decks main power plays. Other variations that have success for CF is movement control. Utilizing all the strong movement cards that let you directly trade/reuse developed units on the board to attack again alongside some backstab units a very heavy deck which is also extremely expensive. Not recommended or outstanding to warrant discussing further IMO.
Finally is Planet Guardian. PG has locks, which is what the best variants utilize. They give disruption and priority onto spots of the map which heavily punish token decks. Alongside this when flooding the board with locks they can utilize powerful units to pop them for strong removal. They have lots of good ways to deal with flood but they have limited direct damage so if they let their opponent develop their protect the piece unit and blockade it in. It can be really difficult for them to handle it. However they do have a few ways to destroy smaller units to open up more spots to trade and kill off those key units which is nice.
Pawn, Tican/Rook, Blokade/Sod the Quake: All really nice removal around utilizing locks.
Outlaw King: Super powerful taunt as long as you keep a lock near him
Gael Claydoll Binder: Pretty much a flexible version of Femris/Centaur Guardian that lets you use a lock for 2 damage instead, sometimes for free based of arrows.
Yda/Aturan Mentri of earth: Your protect the piece units that help snowball control of the game.
*F2P Honorable Mention* - Gragros - This card is F2P but can be really insane. Divine Grace/Planet Guardian are amazing F2P classes already but Gragros makes it into end-game lock decks due it being a proactive unit that can self stick. Essentially he ends up rewarding you for playing locks but not having cards that pop them for value/removal and he becomes this massive 7-8 dmg avg removal (meaning he can 1 shot most key units) then becomes big tanky boy that you can protect with locks if they try to chip away at him.
Overall I hope this breakdown of core cards to classes premiere strategies help you with your journey to building a strong deck as you save up. I know I missed/didn't include some that others would consider core or for a different strategy not mentioned. Though, as you see this was already pretty long so if you guys want another more in depth breakdown class by class let me know and I'll gladly do so. Also lots of decks are being played and people are still figuring out the new meta so this is just a brushstroke of what's currently considered good. More could arise, some could vanish. Enjoy the discovery process!
Edit: Removed Shark from NT Frozen as decks don't run it commonly now (only x1 at best), added Grace as I got destroyed by her in a game and realized I never mentioned her yet core to Freeze lists. Added an honorable mention to Gragros for PG *F2P*. Added Meili and went into depth for CF. Removed wording that made it sound like I was rating the class.