My top 4:
1. Luxray GL X: Easily, and STILL, the best card in the format. A gust with its power, two for 60, and the benefits behind it from being an SP are all astonishing. I see this thing continuing to be the BCIF for next year as well.
2. Garchomp C X: The Healing that this guy has is pretty nice, but the 80 snipe is just amazing. That 80 snipe is beyond useful, with free prizes, or, given fast set up, taking something important out quick. And with DCE around, it's only been stronger (not to say it wasn't amazing before).
3. Pokemon Communication: I'm really shocked no one has said this yet. So what if its blocked by Spiritomb, the fact that it's an SP Radar, essentially, that can be used in anything, combined with the draw we have in this format is pretty sweet. It's really what makes Jumpluff run as well as it does.
4. Broken Time Space: I definitely call this card broken. Despite there also being Rare Candy, the fact that this is around only further breaks things like Jumpluff, allowing it for that turn one set up of not just Jumpluff's, but also things like multiple Claydol. Further, it allows for Pluffs to not have to keep using Candy. And, of course, it benefits other decks like Kingdra, or Donphan.
Had this been a top 10, it would've been easier, as that 4th spot was hard to occupy considering the other broken cards like Jumpluff (as I've constantly mentioned), Expert Belt, things like Power Spray, Poke Turn, etc.