Only Pokemon I’m missing from what has been released is Hippowdon, Gabite, Garchomp, Uxie and Mesprit. That being said, I work hard to keep a perfect Pokedex (equal amounts seen and caught).
EDIT: LOL, I see my own post just a few posts up, but it is outdated. I forgot I even posted here. XD
Jirachi is coming out as well for the general populace in the coming months, and there’s still Kecleon for Hoenn.
There are actually quite a few Pokemon still missing from Sinnoh, mostly Mythicals (Shaymin, Phione, Manaphy, Arceus and Darkrai), but there is still one Legendary (Regigigas), one infant Pokemon (Mime Jr.), and Rotom. The total for Sinnoh should be 107. It’s possible that Sinnoh’s Dex in Pokemon GO won’t be completed for quite a while.