So, I went through that Japanese site that listed all of the nerfs/buffs of moves/abilities this gen, and here's what I got:
Acid Armor = 40 PP -> 20 PP
Air Cutter = 55 power -> 60 power
Air Slash = 20 PP -> 15 PP
Assurance = 50 power -> 60 power
Aura Sphere = 90 power -> 80 power
Barrier = 30 PP -> 20 PP
Blizzard = 120 power -> 110 power
Bubble = 20 power -> 40 power
Charm = Normal-type -> Fairy-type
Chatter = 60 power with a 30% confusion chance at maximum volume of a recording -> 65 power with a 100% confusion chance
Covet = 40 PP -> 25 PP
Crabhammer = 90 power -> 100 power
Draco Meteor = 140 power -> 130 power
Dragon Pulse = 90 power -> 85 power
Dragon Rush = No power/accuracy increase -> Power doubles and never misses if the opponent has used Minimize
Energy Ball = 80 power -> 90 power
Extrasensory = 30 PP -> 20 PP
Fire Blast = 120 power -> 110 power
Fire Pledge = 50 power -> 80 power
Flamethrower = 95 power -> 90 power
Follow Me = +3 priority -> +2 priority
Frost Breath = 40 power -> 60 power
Fury Cutter = 20 power -> 40 power
Future Sight = 100 power -> 120 power
Glare = 90 accuracy -> 100 accuracy
Grass Pledge = 50 power -> 80 power
Gunk Shot = 70 accuracy -> 80 accuracy
Heat Power = 100 power -> 95 power
Hex = 50 power -> 65 power
Hidden Power = Power changes depending on a formula -> Fixed at 60 power
Hurricane = 120 power -> 110 power
Hydro Pump = 120 power -> 110 power
Ice Beam = 95 power -> 90 power
Incinerate = 30 power -> 60 power
Knock Off = 20 power with no power increase -> 65 power with 1.5x if the opponent has a hold item
Leaf Storm = 140 power -> 130 power
Lick = 20 power -> 30 power
Low Sweep = 60 power -> 65 power
Magic Room = -7 priority -> 0 priority
Meteor Mash = 100 power and 85 accuracy -> 90 power and 90 accuracy
Minimize = 20 PP and take double damage from Stomp and Steamroller -> 10 PP and take double damage from Stomp, Dragon Rush, Steamroller, Flying Press, and Phantom Force
Moonlight = Normal-type -> Fairy-type
Mud Sport = Lasts until you switch out -> Lasts five turns
Muddy Water = 95 power -> 90 power
Nature Power = Turns into Earthquake in multiplayer -> Turns into Tri-Attack in multiplayer, but if Misty Terrain is active, turns into Moonblast, if Grassy Terrain is active, turns into Energy Ball, and if Electric Terrain is active, turns into Thunderbolt.
Overheat = 140 power -> 130 power
Pin Missile = 14 power and 85 accuracy -> 25 power and 95 accuracy
Poison Gas = 80 accuracy -> 90 accuracy
Power Gem = 70 power -> 80 power
Rage Powder = +3 priority -> +2 priority
Roar = 100 accuracy -> never misses
Rock Tomb = 50 power and 80 accuracy -> 60 power and 95 accuracy
Secret Power = 30% chance of paralysis in multiplayer -> 30% chance of paralysis in multiplayer, but if Misty Terrain is active, 30% chance of lowering Special Attack 1 stage instead, if Grassy Terrain is active, 30% chance of sleep instead, and if Electric Terrain is active, 30% chance of paralysis.
Skull Bash = 100 power and 15 PP -> 130 power and 10 PP
SmellingSalt = 60 power -> 70 power
Smog = 20 power -> 30 power
Snore = 40 power -> 50 power
Steamroller = Power doubles if the opponent has used Minimize -> Power doubles and never misses if the opponent has used Minimize
Stomp = Power doubles if the opponent has used Minimize -> Power doubles and never misses if the opponent has used Minimize
Storm Throw = 40 power -> 60 power
String Shot = Lowers speed 1 stage -> Lowers speed 2 stages
Struggle Bug = 30 power -> 50 power
Surf = 95 power -> 90 power
Sweet Kiss = Normal-type -> Fairy-type
Sweet Scent = Lowers evasion 1 stage -> Lowers evasion 2 stages
Swords Dance = 30 PP -> 20 PP
Synchronoise = 70 power and 15 PP -> 120 power and 10 PP
Thief = 40 power -> 60 power
Thunder = 120 power -> 110 power
Thunderbolt = 95 power -> 90 power
Toxic = 90 accuracy -> 90 accuracy, except when used by a Poison-type, in which case, never misses, even when the opponent is using Dig, Fly, etc.
Vine Whip = 35 power and 15 PP -> 45 power and 25 PP
Wake-Up Slap = 60 power -> 70 power
Water Pledge = 50 power -> 80 power
Water Sport = Lasts until you switch out -> Lasts five turns
Whirlwind = 100 accuracy -> never misses
Will-O-Wisp = 75 accuracy -> 85 accuracy
Wonder Room = -7 priority -> 0 priority
Sound Moves = Ignore Substitute
Powder Moves = Doesn't affect Grass-types or Pokémon with Overcoat as an ability (Spore, Powder, Stun Spore, Sleep Powder, Cotton Spore, Poison Powder)
Paralyzing Moves = Doesn't affect Electric-types
Drizzle = Now lasts five turns, rather than the whole battle
Drought = Now lasts five turns, rather than the whole battle
Frisk = In a Double Battle, now identifies both of the opponents's held items, rather than just one
Infiltrator = Now ignores Substitute
Oblivious = Now makes the Pokémon immune to the move Taunt
Overcoat = Now makes you immune to Powder Moves
Keen Eye = Now ignores the opponent's evasion boosts
Sand Stream = Now lasts five turns, rather than the whole battle
Sniper = As critical hits now do 1.5x instead of 2x, Sniper makes critical hits do 2.25x, rather than 3x
Snow Warning = Now lasts five turns, rather than the whole battle
