For future reference, you usually give each card it's own row, and the energies have their own section (view other posts for reference). Also, you said 1x Colress twice. Unless, I miscounted, your deck has 60 cards with two Colress, so I'll assume there's two.
Those things aside, I do have a few tips. Here is the summary of my suggestions, and then I'll explain them:
-2 Yveltal BKT
-1 Colress
-1 Scramble Switch
-1 Sableye
-1 Seismitoad EX
+1 Darkrai EX DEX
+1 Darkrai EX BKP
+2 Yveltal XY
+1 Computer Search BCR
+1 Tapu Lele GX GRI
The Yveltal removal is a pretty good idea, in my opinion. Even if the opponent were to load their field up with EXs, you still would have to 4-shot most of them. You 3-shot Shaymin, and 2-shotting Jirachi is the fastest it can know things out. It's just too situational, and too slow. I assumed you have two Colress, so I would recommend getting rid of one. Just having the one there to VS Seeker and use is fine, you don't really need two. Scramble Switch, while it's a super strong card, is an Ace Spec. All Ace Specs are good. This one is just a bit too situational. Computer Search is just a much more consistent, flexible card. You can basically get good use out of it every game. It might not be flashy, you might just have to Computer Search for a Sycamore or something, but you can basically always get something out of it.
Sableye is also a bit situational in my opinion. You already have a one-prize attacker in Yveltal, so it can't serve as the seventh prize card. There are times when it can be game-changing, but again, I think it's a bit situational. Especially with how popular N is, there's a good chance you won't even be able to use the cards you just took.
My last cut is for a reason you might be tired of hearing by now. Too situational. I've tried to make this tech work in a couple decks, and trust me, it's not worth the spot. You basically need to start locking them as soon as possible, or you give them too much time to set up. Once they're set up, they can probably just blow up Seismitoad.
Okay, on to the additions. Basically, the XY Yveltal is a really good card. The energy acceleration, cheap damage, and even tankiness with FFB is really strong. I assume the non BKT Yveltal in your list is the XY/Steam Siege one. The Darkrai EX are intended to make it so you have two Darkrai EX from DEX (the dark cloak one) and one Darkrai from BKP. I had to guess which Darkrai was the one in your list. In the future, I would recommend putting the set abbreviations next to all the cards.
Computer Search and Tapu Lele are for consistency. Not much to say about it, just that consistency is good. That's all there is to it. If you only have one lele, then maybe put the Colress back in.
The main goal of my suggestions are to just remove inconsistencies and streamline the deck. If you don't like them, I apologize. This is honestly what I think would make the deck better. Players are allowed to disagree, and if you do so, feel free do disregard this. Just thought I'd share my thoughts.
Hope this helps, and good luck with this and all your other decks!
