It might seem odd that there isn't quite a lot of time between now and February (the best time for the upcoming game to be released if they're going for the whole "20th anniversary celebration" thing), especially with all of this Zygarde information, and anime information...but hey! Our first gen 4 Pokémon to be revealed was Munchlax in 2004, as part of the Destiny Deoxys movie. DP was also revealed that year during E3.
going by the whole showing u in the anime prior to gen release thing:
ho-oh first showed up in episode 1 of the anime back on April 1, 1997, misty's togepi in episode 50 on June 25, 1998 donphan & mewtwo using shadow ball in the first movie on July 18, 1998 & in the short "pikachu's vacation" maril & snubull first appeared.
ledyba elekid bellossom & hoothoot first showed up in pikachu's rescue adventure on July 17, 1999 (though tracy showed a sketch of elekids plug in ep 103 on July 1, 1999)
also released on July 17, 1999 was slowking & lugia in the "power of one"
gold & silver where released on November 21, 1999
kecleon first showed up in ep205 on July 5, 2001 and tricked a lot of people into believing that purple or green might have been it's shiny color, but like with the pink butterfree that flew off with ash's butterfree to have lots of happy times under the moon, the purple was not the shiny color(though there are purple kecleons running shops in the mystery dungeon series)
wailmer & azurill both showed up in "pikachu's pikaBoo" on July 7, 2001
Pokémon Heroes: Latios & Latias was the first time the 2 in the title showed up, wynuat first showed up in ep252 & duskull & volbeat first showed up in "camp pikachu". pokemon heroes, its short & ep 252 where all released on July 13, 2002
ultra chickenblaziken showed up in ep265 on September 12, 2002
sharpedo seedot shroomish lotad & zigzagoon first showed up in ep 272 on October 11, 2002.
wingull & peilpper showed up in ep274 November 14, 2002
Ruby & Sapphire where released on November 21, 2002
munchlax first showed up in destiny deoxyz on July 17, 2004
lucario, bonsly, weavile & mime Jr showed up in lucario the mystery of mew on July 16, 2005
(on a side note both munchlax & bonsly showed up in xd gale of darkness on August 4, 2005.
this also marked the first time & only time a pokemon could be used with main series mechanics in game made for a gen prior to its own)
manaphy, mantyke, buizel & chatot first showed up in Pokémon Ranger and the Temple of the Sea on July 15, 2006
electivire first showed up in ep468 on September 14, 2006
diamond & pearl where released on September 28, 2006
zoura & zoroark first showed up in Zoroark: Master of Illusionson July 10, 2010 & a symbol resembling woobat is on karl's cap and woobat was announced a day later
Black & white where released on September 18, 2010
Sylveon first showed up in "Eevee & Friends" & mega mewtwo Y in Genesect and the Legend Awakened on July 13, 2013
gogoat & helioptile first showed up in ep 795 on July 18, 2013
noivern first showed up in episode 794 on August 15, 2013
X & Y where released on October 12, 2013
so we should be getting 7th gen pokemon in the anime some time within late 2016 to early 2017
with 7th gen coming out in 2017. so we should be getting another main series game or 2 within 2016 given that the tend to always have at least a year between main series game releases. omegaruby & alphasapphire where released on November 21, 2014 & given that there's still no leaks or anything outside of form change & a recolor, we can't really expect much til at least next year. there's a reason they release main series games more often in the last 4 months of the year or early on in the next year: Christmas.
red & green in february (doesn't really count for much given that it was the initial release of the series though and was 6 years in the making) firered, leafgreem in january
and everything else was though september, october, november, or december except black2 & white 2 which got released june alongside the pokemon radar.
we can also cross off remakes given that we get 2 remakes per system series
gen 3: fire red, leaf green | GBA series + the micro flop
gen 4-5: heart gold soul silver | NDS series
gen 6: omegaruby alpha saphire | 3/2DS series