Blastoise EX

I have no complaints with this deck. I'd suggest Baxcalibur instead of Quaquaval as it's more applicable with water energy, but you don't need a lot of energy acceleration, besides Vitality Spring can work in a pinch. A Blanche could be nice, but it doesn't work great. I think with Baxcalibur to provide energy, Radiant Greninja could be more of a threat. Also try with one less Wartortle. Another key is 4 Irida. That much is needed. 4 Lumineon is also way too many. 1 is plenty, 2 if you really need, but with Irida, you should be fine. You should add a Hisuian Heavy Ball in case Radiant Greninja is prized. Also replace Klara with Nessa, as you have more flexibility. Superior Energy Retrieval is also a good candidate. You also have a very high energy count, which can be cut down to 10 or so. Earthen Vessel is better than Energy Search. Roark is also a bad card, can be replaced with Irida and swap some energy for Superior Energy Retrieval. Twin Cannons having a damage cap is huge, so Lake Acuity is bad for when facing down a Palkia VSTAR. Pokestop is also risky and Calamitous Snowy Mountians doesn't supplement the strategy. I'd swap them all with Artazon or Mesagoza. Boost Shake is also not great as it loses a lot of tempo, but is helpful for getting multiple evolution cards out early like Quaquaval (Baxcalibur if you take my advice) and Blastoise ex in the same turn. Switch cart should be replaced with a switch and an escape rope. It's a nice idea that could be potent with some fine-tuning!

@Tangent

Thank you so much for that advice!!

I will look into your suggestions and build the deck around your tips.  I just started playing the TCG with my girlfriend and we only have level 1 battle decks and one build from the internet, so I wanted to build one myself. I will gladly tell you how it works, if I have it! :)

Dirty Mango Everything I have to say here is what Tangent said, except for one thing, but that depends on how you feel with playing the TCG.

Because Nessa was rotated out last year, using it would make your deck expanded instead of standard. If you're only playing casually, it doesn't really make a difference, but competitive expanded is VERY different from standard, so play at your own risk if you plan on making this expanded. Other than that, I don't really have much else to say.

CountyGibbon798 I didn't realize Nessa rotated, thanks for correcting that.