This set just rocks.
That Shedinja's a nice gimmicky card that could increase it's HP (and therefore max damage output) with Floette from FF. You could also use it with Mew EX and dimension Valley. Though this also opens up the door for Mega Gengar to do up to 10500 damage with Phantom Gate.
Articuno might be the best Pokemon with Delta Plus. It's attack is actually decent and can increase it's odds of hitting better numbers with Fliptini or Trick Coin.
Voltorb is the most broken card in the set and possibly all of Pokemon. I mean, it blows up the table. How is that not OP?
That Deoxys is really good, especially with Dimension Valley.
That Gliscor could be a decent spreader as it's attack cost is just one colorless.
Absol is brings back Sinister Hand. Easier to use, but not as broken. We'll have to see.
Salamance has 3 attacks. Too bad only 1 of them is any good. (though maybe Double Dragon Energy could improve it).
That Unfezant (not the ancient trait one) might be the first decent Unfezant card. Though I wonder if turbulence applies to all cards attached to all Pokemon or just the active.
Good to see Revive is back. Should be fun to try out with Wally in format.
As for the EXes
Thundurus is average at best. Neither attack stands out as being particularly good or useful, but they aren't terrible either.
Gallade is unique. It maxes out at 170 and will always hit for at least 70. 3 Psychic energy is a hefty cost, but I guess you could always mega evolve, mega turbo, and then use Memory Shrine or Celebi EX to use the basic's attack. Though Mega Gallade's attack is nothing to scoff at either (possible combo with Forrettress?).
Latias: Ugh. This is not going to be good for evolution decks which rely on weak basics. Not sure what to think about the Mega.
Hydreigon: This could be part of an energy acceleration engine with Reshiram. Just use Reshiram's power to get an additional energy in play and then use double dragon energy. With a stadium in play, and Hydreigon benched, Reshiram can retreat into what ever you want to attack with. Most Dragon Pokemon (including Hydreigon itself) have attacks which require 2 different types of energy and a colorless. The fire can provide the colorless while double dragon takes care of the complicated part.
Rayquaza: Nice to see a splashable fighting resistant Pokemon. Rising burn alone might make this worth a spot. The mega is just broken with Skyfield. Wouldn't be surprised if it becomes BDIF.
Shaymin is another game changer. Actually much better than Jirachi. You can use the ability and still play your draw supporter. And the attack is actually useful.
Final verdict: Cool set. A lot of fun strategies are opened up with this.