Those sort of items are called vitamins. The following X and Y locations:
HP UP:
>Battle Maison and Laverre City Poké Mart, Route 8, Route 15, Route 19, Lost Hotel (Trash Cans), PokéMileage Club (Graffiti Eraser, Lv. 3)
Protein:
>Battle Maison and Laverre City Poké Mart, Lumiose City (Centrico Boulevard), Cyllage City, Route 15, Route 20, Lost Hotel (Trash Cans), PokéMileage Club (Graffiti Eraser, Lv. 1)
Iron:
>Battle Maison and Laverre City Poké Mart, Reflection Cave, Lost Hotel (Trash Cans), Terminus Cave, PokéMileage Club (Graffiti Eraser, Lv. 2)
Calcium:
>Battle Maison and Laverre City Poké Mart, Route 17, Lost Hotel (Trash Cans), PokéMileage Club (Graffiti Eraser, Lv. 1)
Zinc:
>Battle Maison and Laverre City Poké Mart, Lost Hotel (Trash Cans), Frost Cavern, Victory Road, PokéMileage Club (Graffiti Eraser, Lv. 2)
Carbos:
>Battle Maison and Laverre City Poké Mart, Lost Hotel (Trash Cans), Victory Road, PokéMileage Club (Graffiti Eraser, Lv. 3)
The following three aren't really stat-raising, but they raise PP and level.
PP UP:
>Loto-ID Center (2 digits), Lumiose City South Boulevard Pokémon Center, Route 19, Super Training, PokéMileage Club (PokéMileage Shop; Graffiti Eraser, all levels), Pickup, Kiloude City, Route 7, Route 13, Route 15, Route 18, Route 21, Frost Cavern, Victory Road
PP Max:
>Loto-ID Center (3 Digits), Super Training, PokéMileage Club (Graffiti Eraser, all levels)
Rare Candy:
>Pickup, Lumiose City South Boulevard Pokémon Center, Battle Maison, PokéMileage Club (PokéMileage Shop; Graffiti Eraser, all levels), Ambrette Town, Couriway Town, Route 13, Route 14, Route 16, Route 17, Route 18 (from Psychic Inver), Route 21, Parfum Palace, Lysandre Labs, Victory Road
Note, the actual stat-raising items can all be found in Laverre and the Battle Maison Pokemart.
Hope I helped. :)
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