Zygarde 10% form, Alakazam EX and M Alakazam EX English cards have been revealed by Pokémon, along with an image of the set logo, and also, the set numbering.
As you can see on the cards, the set will contain 124 cards, not including secret rares that may be included.
There’s also been some artwork released featuring Zygarde in its 100% form.
The Pokémon website has also revealed this description for the set:
Reality shifts and is remade in the Pokémon TCG: XY—Fates Collideexpansion! Mega Alakazam-EX sees the future—and shapes it to unify two worlds! The Legendary Pokémon Zygarde arrives in many different Formes to bring order, together with Lugia BREAK, Mega Altaria-EX, and Umbreon-EX. Fates are sealed, and two Pokémon worlds join together!
Check out our TCG releases page for more information on Fates Collide, including all products it will contain revealed so far.