MEGA Dream ex  will release in Japan on Friday, November 28th!

The set will be headlined by Mega Dragonite ex, but also feature a large number of Mega Evolution Pokemon. There are currently 49 Mega Evolutions, with more to come in Legends: Z-A.

There will be a new rarity called "Mega Stone Mirror." This could be a new reverse holo style for the set's Mega Evolutions, perhaps featuring their Mega Stones in the holo foiling instead of Poke Balls. (But that's just my speculation.)

MEGA Dream ex will be Japan's annual High Class Pack set. Each booster pack will contain 10 cards instead of the usual five, including a guaranteed hit.