Anyone got tips on what makes a good deck?
Seen some good comments in this thread but thought I'd weigh in a bit too. There's different kinds of playstyles in Card Games which typically boil down to:
Aggressive / Hyper Offence (Aggro)
Aggro Decks are fast-paced, you don't want to waste too many turns doing things other than dealing damage or gaining points (whichever the win condition is for said game). Pocket is a bit of both, dealing the most damage as quick as possible to gain your 3 Points first. They're low to the ground, so in this game you generally wouldn't want Pokemon that need more than 2 Energy to attack.
Slower / Build Up (Control)
Control decks tend to try and build up their resources and game pieces in the early stages of the game to then be able to take over the game in the later turns, trying not to get overwhelmed early and then turning the tables. Usually these decks would need heavy resources to have bigger end-game threats, in this game think Mewtwo ex and Charizard ex.
Bit of Both (Mid-Range)
Mid-Range decks try to fit both of the above, but as the name would say they fall a bit in-between and aren't quite as good at the aggressive part or the Control part. Typically stronger in the mid-game (no surprise). However, they can definitely be some of the best decks even if it doesn't quite sound like it there. I would say though that they tend to be the more difficult deck to play for newer TCG players. This is because the decks are designed to be flexible and you need to be able to understand when you are the aggressor or not. There tends to be more decisions to make each turn compared with the other decks, which while great for very knowledgeable and experienced players, can also be a negative as it means there are more opportunities for you to make the wrong decision.
Aggro decks tend to be the best way for newer players to learn the game IMO, but you should of course eventually try to play lots of matches will all kind of decks until something clicks for you and you know what kind of player you are.
For deck building in this game, I think it's good to look at what the packs can offer and honing in on a particular pack at first to have a greater chance of building the optimised version of that deck. The pack arts (Charizard, Pikachu, Mewtwo) have some cards that are specific to them, while there is a selection of cards that can be found across all three packs. I wouldn't worry too much if you haven't been doing this, but once you have decided on a deck I would just keep opening those packs until you can build that deck - or at least get extremely close and use Pack Points to buy the missing card(s). I would advise using Pack Points on Supporter Cards mainly as they have been somewhat difficult to pull and are the glue that brings some decks together.
The two most popular decks are Pikachu ex & Mewtwo ex but they're both beatable and might have quite different builds. Pikachu can go with a lot of different cards, but Mewtwo tends to need Gardevoir which makes it quite slow in the early game and you may find yourself not managing to get Gardevoir in play at all (and you'll probably end up losing half the time or more if you don't). I'll list a few decks but I'm going to start with an Aggro one which is really strong and should be quite easy for most people to build:
Blaine Deck
2 Ponyta
2 Rapidash
2 Vulpix
2 Ninetales
2 PokeBall
2 X Speed
2 Professor's Research
2 Blaine
2 Giovanni
2 Sabrina
I love playing this deck as it's fun and super fast. You might lose quick, but you'll win a lot of games quick once you get the hang of it. It can also make great use of the extra damage from Supporter Cards and utilises Sabrina really well to pick KOs when people overload their bench. If they don't manage to get 130+ HP Pokemon into play early then you can overwhelm them. As said above, you want to go fast and deal damage almost every turn. Ponyta is a good lead and can then evolve the next turn to deal 40 Damage with Rapidash (50 or 70 with Supporters) which is great by your second turn. You can then build up Vulpix into Ninetales on the bench and hopefully be able to keep swinging into things for 90-120 by added one Energy each turn. X Speed is great as it allows you to switch around without spending the Energy Cards, as everything only has a One Retreat Cost. I don't think you need to waste time with trying to fit in cards like Moltres, Magmar, Potion, Red Card etc like some try to. Just go 2 of all of the above cards and hope you can keep the pressure on. You can get all of these cards in Charizard Packs except for Giovanni and the Shop Exclusive Trainer's like X Speed, PokeBall and Professor's Research, but they're easily affordable with Shop Tickets. If you're missing some of the Supporters and can't buy them with Pack Points, that's when you can just drop in some other cards like Heatmor, Magmar, Moltres ex, Farfetch'd, or Trainers like Red Card and Potion just as a gap filler.
Primeape Deck
2 Mankey (017/P-A)
2 Primeape
2 Diglett
2 Dugtrio
2 Cubone
2 Marowak ex
2 X Speed
2 PokeBall
2 Professor's Research
2 Sabrina
There's an event going on at the moment (Lapras ex) where you can get this Mankey card so play lots of that to get some. This deck is a bit more flexible than the Blaine one IMO in terms of which cards you can choose. Diglett/Dugtrio could be replaced with Sandshrew/Sandslash, or even cut entirely and just go with the Mankey and Marowak lines. You also have access to a regular Marowak card just in case you didn't pull 2 ex variants. Giovanni can easily go into this deck, as can Potion but it's a bit clunky at times since you want damage on Primeape so he can deal 100 with his attack. The Promo Mankey has made this deck playable as it deals 10 damage to itself when it attacks (smarter players would just not attack Mankey/Primeape until they could one-shot them). Red Card is always a decent filler choice if you can't complete the deck, but I'd only really use it if it looks like your opponent has been heavily leaning into a particular bench Pokemon (eg. They've put 2-3 Energy on their Charmeleon) which means it's probably somewhat likely they have Charizard ex in their hand. Or more optimally, using Red Card when your opponent has 4+ cards and has used up most of their Professor's Research/PokeBall and can't rely on them to draw additional cards for the rest of the game.
If you want to build Pikachu or Mewtwo, or some of the other ex decks, then obviously just lean heavily into opening those booster packs. However, these decks really need 2 copies of the ex card to function consistently and it's more likely that you can hit the lesser rare cards to use the decks above faster. The more you win battles on random match, in the battle event, in the other events and solo play, the quicker you will level up. Every level up gives you 12 Hourglasses I believe (an extra pack at worst), so even if you're mostly a collector it's well worth investing in this as it will allow you to open more packs. I can post in some other decks, but it might be better watching some YouTubers that have decks showcased. Another more decent budget option is Exeggutor ex, I was using that early on as I opened Charizard packs first and managed to get 2 in my first 20 packs.
The game is still fresh and more will be figured out, but I think the best cards in the game are probably:
Sabrina
Professor's Research
PokeBall
Pikachu ex
Starmie ex
Mewtwo ex
Some other contenders as well like Misty being able to cheat out wins, but it isn't as consistent as the above cards, they're just really good.