Wow, that Shuckle is actually busted. Immediate basic energy discard for a variety of things like Malamar, Metagross (probably not a good idea but gonna mention it either-way), Alolan Exeguttor, maybe even Mt. Coronet to get the energies straight out of your deck, but my favorite personal use for this guy will probably be the new Rayquaza-GX coming out. Get energies in your discard pile, use Latias PS (or Zeraora-GX since it's coming in the same set as this one) to charge up multiple Rayquazas and murder. And on top of all that, it's an energy accelerator in itself. The same kind of attack that Lurantis-GX has, except it's basic and it's prize one. Just like Forbidden Light will do to Buzzwole, this Shuckle will do to Rayquaza, mark my words.
As for the other cards, White Kyurem's a pretty neat little tech for any deck using DCE. It's a water attacker that can destroy stadiums, not the worst thing I've ever seen. Electivire would get knocked out before it even has all the energies on it, and that Onix better evolve if you're gonna make me play something that does 120 flat for 4 colorless energy (Steelix-GX would be dope though).