Venusaurite - Area Before Safari Zone (The lil area before the town)
Blastoisinite - Whirl Islands (Water Area and fits the Ability)
Alakazite - In Sabrina's Gym (Cause She uses one)
Gengarite - By Slenderman (Super Scary No Face men... Cause of Creppypasta reasons)
Kangaskhanite - Day Care in Kanto (Cause she is the Gen 1 Mommy)
Gyaradosite - In the Pokemon Center Near Mt.Moon (Cause that dude in the first game who sold Magikarp)
Aerodactylite - NPC in Pokemon Center On Cinnabar Ruins (The old place where you could get one was there)
Ampharosite - On the lil Island near Cherrygrove (Was found on Simular Island in X and Y and is given early enought to be useable)
Scizorite - In the Berry Forest in the Room where you fought one. (Reason... I think it speaks for itself)
Blazikenite - Where Volcanon was. Make it near or in the same room. (lava and heat and it is later game so the player isn't to op)
Gardevoirite - Day Care Center in Sevii Island (Looks like a Mother and was one many times in the Anime and Manga)
Mawilite - Mewtwo's Room where the Black Sluge was (Mawile is in caves and is a Fariy the can handle Poison)
Medichamite - the Dancing theather (The Dancer Girls Talk about peace and Medicham is based off the Budda Belifes to it fits a lil)
Banettite - Beside Morty (Gym Matches... Best Idea I had)
Absolite - Dark Cave, Near Blackthorn (Dark Cave Matches Type, Area Absol would be found, Later game but not to late)
Garchompite - Dragon's Den Being Guarded by a Trainer (Late game but once again Be for Elite 4 so not to late)
Lucarionite - New Bark Town, where your Rival was. (The First mega stone most players got to use and would be fitting in that town as well as your Rival's fighting spirt)
Abomasite - Ice Cave in the Middle of the cave (Fits in Candice's Gym who used an Abomasnow, and makes is usabble before the dragon gym)
Charizardite X - Near where red is Standing (Red uses One in Cannon)
Pinsirite - In Viridain Forest (Pinsir was the main Bug for 1st Gen (Outside Syther but He gets a mega and evole) so it would fit really well actually)
Mewtwonite X - The Area to the Right on entry of the Cerulain Cave, Over the little Hill (Mewtwo's Cave and is needs you to go thru the cave)
Tyranitarite - Victory Road (Rock type and Perfect Because be for Elite 4)
Manectite - Power Plant in Kanto (The Lightning Gym in Hoenn Ways in a power plant and he used a Manectie)
Charizardite Y - By/In Mr.Fuji's Home. (He Gave Red The x and could have the y sitting around)
Mewtwonite Y - By the spot where Mewtwo was caught (Cannon Mega for Mewtwo)
Heracronite - In Azelia Town By/in a Tree (Is the Bug for 2nd Gen and fits in that locaton with type and color)
Houndoominite - In Victory Road Higher up. (Before Elite 4, Powerful pokemon in powerful area, dark cave)
Aggronite - Mt.Moon (Aggron is a cave pokemon, after Elite 4)
Beedrilite - Viredian Forest (Home of Weedle)
Pidgeotite - The Little House Near Celadon Above cycling Road where in the First Gen you got fly (FLY LIKE A BIRD!)
Slowbronite - In Cerulain Cave Near Water (Slowbro are found in the cave)
Steelixite - Where the Girl Gave you Metal Coat in FRLG (Here Onix died there and it's stones harden under ground into the stone)
Sceptilite - In the Berry Forest (The Yellow Balls Look like Berries and he is a grass type)
Swampertite - The Hot Spring In sevii (Later Game)
Sablenite - Toko Falls in little Room (Darker area)
Sharpedonite - In the Junk Area In Sevii with the Invis Iteams on that on Shore Line ( A stone has to be there)
Cameruptite - In Volcanon's Room (He is what he is...)
Altarianite - Lake of Rage (Not to op and Later in game to allow actual use of that mega)
Glalitite - Ice Area Below Blaine's Gym (Later Game to prevent op and is in a very "Ice" Area)
Salamencite - In Lance's Room at the Elite Four (Want it after Elite 4 and Before Kanto Gyms so it is not op or to weak)
Metagrossite - Given to you for seeing the Game Grumps Easter Egg (Best Mega outside the main 2 and is great for manipulation as well as keeping the player quite about what they saw.
Latiasite - On the Island Of Mew (Female Dragon likes Mew cuz SO CUTE!)
Latiosite - Chuck's Gym (Manly Dragon, Manly Gym)
Lopunnite - In Jasmine's Gym (Cause they sexy... Best I got)
Audinite - Day Care Center in Jhoto
Galladite - The Start Mt. Sliver
Diancite - Event or on Her on Capture when added into game
Mega Rayquaza - Rayquaza doesn't need to Mega Stone to Mega Evolve. Instead, it needs to learn the move Dragon Ascent in order to be able to Mega Evolve. So Make Lance, a Dragon Elder or Dragon Gym Leader a Move Tutor for it.