Gabite and Garchomp: Ground and Fighting seem better suited to them than Ground and Dragon .. *gasp*
Elekid, Electabuzz, Electivire: Electric and Fighting, I mean, really?
Masquerain: Keep the Bug and Water of Surskit, please?
Gyarados: Shouldn't be Flying type, it doesn't fly, why not keep it a plain Water type? Water and Dark for the Mega is acceptable, though.
Chikorita, Bayleef, Meganium: Grass and Ground, though I'm not so sure about that.
Cottonee, Whimsicott, Azurill, Marill, Azumarill, Dedenne: Why are they Fairy type?
Gligar, Gliscor: Ground and Poison, they're gliders, not fliers! And Poison type is totally fitting for scorpions, right?
Emolga: Electric and not Flying, by similar reasoning
Tornadus, Thundurus, Landorus: Incarnate forms do not look like Flying types! Isn't a simple Levitate enough?
Cresselia: Adding the Fairy type would help it greatly, and cancel the disadvantage against Darkrai!
Darkrai: Dark and Ghost seems sensible, right?
Shaymin: Land form isn't Ground type? Whoops...
Victini: Seems more like a Fairy type than Psychic..
Xerneas: Grass type could level its advantage over Yveltal
Glalie: This is a Rock, isn't it?