I do not work at GameFreak or know someone who does.
I'm not lying to you, or making anything up.
I do not claim to be right, but I do claim to believe what I am about to tell you.

I had this dream. I did not know I was dreaming until several minutes after I woke up.

I dreamt that I was reading a magazine, that had a chart listing new abilities, including one signature ability - Cute Heart.
Cute Heart morphs into one of three abilities at the end of every turn, but are all counted as the original ability (if Gastro Acid, Role Play, Trace, etc. are used)
Ability one: Reduces the base power of Fire moves by 50%
Ability two: Reduces the base power of Water moves by 50%
Ability three: Reduces the base power of Grass moves by 50%
Note this obviously means defensively. So effectively halving the damage taken from all three starter types.

As you may have guessed, this is the signature ability of Sylveon - The Dragon of Spring. That's right, Sylveon evolves based on the season, and is Dragon-typed. That, or its still normal with a resistance-boosting ability, though I think I recall it saying its a Dragon. I know not what trigger activates the precise evolution. Glaceon and Leafeon may or may not be retconned to Winter and Summer evos. If this is the case, no hint as for the autumn evolution, if any.
I also do not remember the rest of the new abilities. However, there were something like 8-12 new ones, at least. They are not exclusive to Gen VI mons, but I have no clue as to who gets a new ability.