I really don't think the Koko Promo goes in here and here is why. First the energy doesn't match up, you don't want to run the GX with Double Colorless, and you don't want to run the promo without. Next think about where the Promo is useful, it's a retreat outlet and it helps push things like Ninetales with 160 damage attacks into OHKO range, while the GX is very unlikely to OHKO, without using the GX attack, but very likely to 2 shot. It's use as a retreat outlet, for something like Guzma with something like Golisopod is another one of it's uses, but the point here is to be cycling the GX. You already have something like Raikou to make it a 7 prize game, so you gain no value there. This is actually a very unique occurrence, because normally the Baby card synergies with it's Ultra rare i.e. Yveltals, Volcanions.
To respond to this, I will admit that it is not the forerunner of the meta, and it is largely rogue, but it's a great response to all these slow decks currently in the format. Once you build a deck that always swings turn to the only thing that keeps pace with it currently is Drampa, and you have FFB and stadium that need to be countered in order for Drampa to OHKO, and it needs its choice band and it's own stadium to have been out, so even it should be slower. 130 twice is an unavoidable 2HKO, perhaps only a lucky Tapu Bulu, Vikavolt deck would survive those first 2 turns. With fast decks like Vespiquen, and Rayquaza, or any Forest nonsense, out of Standard it seems to be about powerful mid-late games, Gardevoir, Garbodor, Golisopod, and Ninetales showing at worlds. If this deck is properly made and executed Gardevoir will lose a line or 2 before it setups, and then a setup line to the GX attack. This should leave about 2 prizes to take, and from there 2HKO's should be fine. It is all about consistently, so once those are ironed about it's all about swinging turn 2 and never letting up. And it doesn't mind going second as with 2 max elixir hits it could swing right then and there and KO any pesky basic setup pokemon i.e Yveltal, Xerneas, Vulpix, or basics of stage 2's.
