We get a glimpse of a handful of new Pokemon in the trailer.
Litleo: A fire/normal Lion Cub pokemon.
Flabébé: A new fairy that lives on flowers of different colors(what the site says, but only red in pics so far.)
As well as a glimpse into our first full evolutionary chain.
Scatterbug -> Spewpa -> Vivilion
You can also read some in depth info about your entororage of friends at the Pokemon XY website.