Like all new main Pokémon games, Pokémon X & Y introduce a new bunch of items into the mix. These items are mostly Key Items and can be used for a variety of different features. They are as follows

Picture Name Effect
Ability Capsule A capsule that allows a Pokémon with two Abilities to switch between these abilities when it is used
Abomasite One of the mysterious Mega Stones. Have Abomasnow hold it, and this stone will enable it to Mega Evolve in battle
Absolite One of the mysterious Mega Stones. Have Absol hold it, and this stone will enable it to Mega Evolve in battle
Adventure Rules This book contains all points a new trainer needs to know on a journey. It was handmade by a kind friend
Aerodactylite One of the mysterious Mega Stones. Have Aerodactyl hold it, and this stone will enable it to Mega Evolve in battle
Aggronite One of the mysterious Mega Stones. Have Aggron hold it, and this stone will enable it to Mega Evolve in battle
Alakazite One of the mysterious Mega Stones. Have Alakazam hold it, and this stone will enable it to Mega Evolve in battle
Amaze Mulch Mulch to be used in a Berry field. An amazing Mulch with the effects of Rich, Surprise and Boost Mulch
Ampharosite One of the mysterious Mega Stones. Have Ampharos hold it, and this stone will enable it to Mega Evolve in battle
Assault Vest An item to be held by a Pokémon. This offensive vest raises Sp. Def but prevents the use of status moves.
Banettite One of the mysterious Mega Stones. Have Banette hold it, and this stone will enable it to Mega Evolve in battle
Blastoisinite One of the mysterious Mega Stones. Have Blastoise hold it, and this stone will enable it to Mega Evolve in battle
Blazikenite One of the mysterious Mega Stones. Have Blaziken hold it, and this stone will enable it to Mega Evolve in battle
Boost Mulch Mulch to be used in a Berry Field. It increases the Berry harvest that can be grown by diligent watering.
Charizardite X One of the mysterious Mega Stones. Have Charizard hold it, and this stone will enable it to Mega Evolve in battle
Charizardite Y One of the mysterious Mega Stones. Have Charizard hold it, and this stone will enable it to Mega Evolve in battle
Discount Coupon This special coupon allows you to buy items at a discount when you are shopping at a boutique.
Dowsing Machine It searches for hidden items in the area and emits different lights and sounds when it detects something.
Elevator Key A card key that activates the elevator in Lysandre Labs. It is emblazoned with Team Flare's logo
Garchompite One of the mysterious Mega Stones. Have Garchomp hold it, and this stone will enable it to Mega Evolve in battle
Gardevoirite One of the mysterious Mega Stones. Have Gardevoir hold it, and this stone will enable it to Mega Evolve in battle
Gengarite One of the mysterious Mega Stones. Have Gengar hold it, and this stone will enable it to Mega Evolve in battle
Gyaradosite One of the mysterious Mega Stones. Have Gyarados hold it, and this stone will enable it to Mega Evolve in battle
Heracronite One of the mysterious Mega Stones. Have Heracross hold it, and this stone will enable it to Mega Evolve in battle
Holo Caster A device that allows users to recive and view hologram clips at any time. It is also used to chat with others
Honor of Kalos A precious symbol that is awarded only to an individual who has done great things for the Kalos region.
Houndoominite One of the mysterious Mega Stones. Have Houndoom hold it, and this stone will enable it to Mega Evolve in battle
Intriguing Stone A rather curious stone that might appear to be valuable to some. It's all in the eye of the beholder.
Jaw Fossil A fossil of an ancient Pokémon that lived in the sea in ancient times. It appears to be part of its jaw
Kangaskhanite One of the mysterious Mega Stones. Have Kangaskhan hold it, and this stone will enable it to Mega Evolve in battle
Kee Berry If held by a Pokémon, this Berry will increase the Pokémon's Defense stat when hit by a physical attack
Lens Case A rather chic-looking case for carrying contact lenses
Looker Ticket A ticket that was handmade by Looker. It's decorated with a liberal amount of glittery paint.
Lucarionite One of the mysterious Mega Stones. Have Lucario hold it, and this stone will enable it to Mega Evolve in battle
Luminous Moss An item to be held by a Pokémon. It boosts Sp. Def if hit with a Water-type attack. It can only be used once.
Lumiose Galette A popular treat in Lumiose City. It can be used once to heal all the status conditions of a Pokémon
Manectite One of the mysterious Mega Stones. Have Manectric hold it, and this stone will enable it to Mega Evolve in battle
Maranga Berry If held by a Pokémon, this Berry will increase the Pokémon's Sp. Defense stat when hit by a special attack
Mawilite One of the mysterious Mega Stones. Have Mawile hold it, and this stone will enable it to Mega Evolve in battle
Medichamite One of the mysterious Mega Stones. Have Medicham hold it, and this stone will enable it to Mega Evolve in battle
Mega Ring This ring contains an untold power that somehow enables Pokémon carrying Mega Stones to Mega Evolve in Battle
Mewtwonite X One of the mysterious Mega Stones. Have Mewtwo hold it, and this stone will enable it to Mega Evolve in battle
Mewtwonite Y One of the mysterious Mega Stones. Have Mewtwo hold it, and this stone will enable it to Mega Evolve in battle
Pinsirite One of the mysterious Mega Stones. Have Pinsir hold it, and this stone will enable it to Mega Evolve in battle
Pixie Plate An item to be held by a Pokémon. It is a stone tablet that boosts the power of Fairy-type moves
Power Plant Pass This pass serves as an ID card for gaining access to the power plant that lies along Route 13
Prof's Letter A letter that Professor Sycamore wrote to your mother. A faint but pleasant perfume seems to cling to the paper.
Rich Mulch Mulch to be used in a Berry Field. It increases the Berry harvest without the need for particularly diligent care.
Roller Skates Attaches roller skates to the bottom of your shoes, allowing you to glide quickly around and perform tricks
Roseli Berry If held by a Pokémon, this Berry will lessen the damage taken from one supereffective Fairy-type attack
Sachet A sachet filled with fragrant perfumes that are just slightly too overwhelming. Yet it's loved by a certain Pokémon
Safety Goggles An item to be held by a Pokémon. These goggles protect the holder from both weather-related damage and powder.
Sail Fossil A fossil of an ancient Pokémon that lived in the sea in ancient times. It appears to be part of its sail
Scizorite One of the mysterious Mega Stones. Have Scizor hold it, and this stone will enable it to Mega Evolve in battle
Snowball An item to be held by a Pokémon. It boosts Attack if hit with an Ice-type attack. It can only be used once.
Sprinklotad A watering can shaped like a Lotad. It helps promote the healthy growth of any Berries planted in good, soft soil.
Strange Souvenir An ornament depicting a Pokémon that is venerated as a protector in some region far from Kalos
Surprise Mulch Mulch to be used in a Berry Field. It causes strange, sudden mutations based on the combination of Berries.
TMV Pass A commuter pass that allows the holder to ride the TMV between Lumiose City and Kiloude City at any time
Tyranitarite One of the mysterious Mega Stones. Have Tyranitar hold it, and this stone will enable it to Mega Evolve in battle
Venusaurite One of the mysterious Mega Stones. Have Venusaur hold it, and this stone will enable it to Mega Evolve in battle
Weakness Policy An item to be held by a Pokémon. Attack and Sp. Atk sharply increase if the holder is hit with a move it's weak to.
Whipped Dream A soft and sweet treatmade of fluffy, puffy, whipped and whirled cream. It's loved by a certain Pokémon