1 Shaymin Celebration Wind
Pokemon Total = 15 cards
4 Pokemon Collector
1 Professor Elm's Training Metho
3 Junk Arm
3 Research Record
3 Pokemon Communication
3 Pokemon Catcher
2 Super Rod
Trainer/Supporter Total = 29 cards
4 Water Energy
4 Metal Energy
4 Rainbow Energy
4 Metal Energy (Special)
Energy Total = 16
This energy acceleration engine of this deck is the electrode prime. You give up a prize to use it, but then get to discard several cards from your deck, attaching any energy you find. This lets you do several different strategies depending on what you're playing against. Kyurem spreading damage will let you take many prizes late in the game while cobalion can prevent key pokemon from attacking.
With lightning being a huge part of the meta, I'd include terrakion as one of the main attackers. I'd probably drop 2 coballion and add in 2 terrakion.
With terrakion being a new attacker, you can drop the basic metal in exchange for basic fighting energy. Since all of your pokemon are basic, you can now use the new prism energy instead of rainbow and not have to take the damage counter that rainbow energy forced on you.
Increase your twins to 4 to take advantage of the prizes that you'll be giving with electrode prime. That will help you finish getting set up early in the game and will help ensure that you make a comeback. I'm not a fan of elm unless you have an extremely heavy trainer lock area. You have quite a few heavy retreaters, so an additional switch should be added to make sure you can get your pokemon out of a bind without giving up the energy. This deck doesn't really work well on low hand sizes, so it should be safe to drop the N in favor for another draw supporter like PONT. You should only need one super rod in the deck since you can reuse it if you need to with junk arm (which I'd also max out to 4).
CaKE/CoKE was a top tier deck in this past cities. It's still easily in the top 10 decks, but with all the speed of the lightning decks, it'll be interested to see whether it can remain a top deck. The reason why I didn't suggest adding in any EX pokemon was because you're already giving up multiple prizes with electrode and EX's will ensure your opponent victory by cutting their work to earn prizes down by half.