Clauncher, Skrelp, Orotto, Dedenne, Noivern, Xerneas, and Yveltal.
These are the only Pokemon that we don't know the location of in the dex. Clauncher and Skrelp will probably go in Coastal, Orotto and/or Dedenne could probably end up with a single space in either Coastal or Central.
There is still an entire Mountain region that is unaccounted for. No leaker has even begun to scratch the surface. Too many of them probably grinded to see the final evolved forms for the starters because that was what EVERYONE really wanted to see. So, I bet there are only like 1-2 people who have even begun to get into the nitty gritty of postgame. A few tops.
I fully believe that we will have ~100 new Pokemon, and a majority of those that we don't know of will be in the Mountain region. Remember Heatmor, the Foongus line, Golurk line, Druggidon, hell go back to Gen 4 and look at Abomasnow. There are always Pokemon you don't see until LATE game.