The sixth generation of Pokémon brought forth one of the most beloved new features of the entire franchise: Mega Evolution. X & Y introduced many of these new forms, creating some of the strongest Pocket Monsters in existence. Players may be interested in finding the most powerful creatures in the region to use in a playthrough. Certain Mega Evolved, Legendary, and Mythical Pokémon are the strongest in the region, but this may be obvious.
The Kalos region also features some other strong Pokémon that deserve recognition. The website Serebii.net features information to help evaluate the strength of Pokémon. Although the Kalos region introduced the fewest evolutionary lines out of any region, it gave the franchise some incredible Pocket Monsters.
Chesnaught
From Generation III to Generation VI, the Fighting secondary type was always present on one of the starters' final evolutions. Chesnaught was the first Grass-type starter to receive this typing. This gives Chesnaught the capability to use both Grass and Fighting moves with a Same Type Attack Bonus, and its Attack stat helps it greatly. It is terribly slow and has low Special Defense, though, so if a super-effective Special move hits it, it would likely knock Chesnaught out. It needs proper matchups to be incredible, but it can exceed expectations in these situations.
Sylveon
The most recent addition to the Eevee family, Sylveon is a beloved creature of the Pokémon world. Although it struggles on the Physical front, it excels with its Special stats, as its Fairy typing suggests. This type is an exceptional one, being able to counter the often overpowered Dragon-type. This is one of the reasons Sylveon is one of the best Eeveelutions in Pokémon. Unfortunately, it has terrible Speed, so if it is faced with an opponent with a high Attack stat, Sylveon is likely doomed. Against other Special attackers or balanced attackers, though, Sylveon is quite powerful.
Tyrantrum
The massive dinosaur-like Tyrantrum is a monster of a Physical specialist. Its Attack and Defense are stellar, which lets it strike with massive force and defend against Physical attacks with relative ease. It runs into trouble, though, when it comes to Special moves. Its Special Defense is laughable, making it a target for these kinds of attacks. Its HP is decent, but it often does not help enough during poor matchups. Players must use Tyrantrum carefully, and when they do so, it can be incredibly destructive to opposing teams.
Florges
Although Florges resembles a flower, it is a pure Fairy-type. As such, it has a great Special Attack stat. There is a downside to using Florges, though. Its Defense and Speed are sub-par. As its appearance suggests, it has access to many Grass-type attacks.
While these do not receive a boost from being the same type as Florges, they can still do extensive damage using the Pokémon's high Special Attack. In neutral matchups, Florges is more than capable of holding its own against enemies.
Goodra
As far as pseudo-Legendaries go, Goodra is less impressive than its peers. Its Special Defense is ridiculously high, but this is at the sacrifice of its Defense and Speed. Goodra is a pseudo-Legendary nonetheless, and as such, it has a high base stat total. Its Attack and Special Attack are high and fairly even, giving it viable access to the multitude of moves it can learn.
Although its pure Dragon typing can be limiting, its high offensive stats let it use these moves with great strength. The pure Dragon typing also means it has no extreme vulnerabilities. This is something that fellow pseudo-Legendaries like Dragonite and Tyranitar cannot boast.
Delphox
Delphox hits quickly and with great power, but it can suffer if it does not defeat opponents in one turn. It has a high Speed stat and a great Special Attack stat, but it hits a barrier against foes with strong Physical attacks. This is why Delphox is one of the worst final forms of a Fire-type starter. However, as a fully evolved starter Pokémon, Delphox is still quite powerful. As long as it can knock out opponents rapidly, it can shine. With many Special Fire and Psychic moves, Delphox is capable of doing this with ease.
Gogoat
The "Mount Pokémon" Gogoat has more functionality in X & Y than simply being a shuttle. Although it does not have exceptional defensive stats, its HP helps to make up for this. This bulk allows it to use its relatively high Attack and Special Attack to retaliate against foes.
Although the two offensive stats are similarly high, Gogoat benefits more from the Physical category. This is because every attack it learns from leveling up is Physical. It can also access moves like Seed Bomb, Horn Leech, and Leaf Blade, which increase its viability.
Aurorus
Aurorus mostly relies on its heavy bulk to carry it through battles, but it does so excellently. It has mediocre Physical stats, which can be an issue for it in many situations. It does have higher Special stats, though. On the defensive side, this helps Aurorus to withstand many attacks of this category.
On the offensive side, this lets it use its many Special attacks with great power. Aurorus does not have a great Speed stat, but it can normally take several attacks before it goes down thanks to its high HP. If it avoids Fighting and Steel-type moves, it can be a great choice.
Greninja
Upon its introduction, Greninja quickly became a fan favorite, even becoming one of the best Pokémon fighters in Super Smash Bros. This fame is largely due to its absurd power in X & Y. Its defensive stats are abysmal, but its offensive stats are monstrous. This is paired with its extremely high Speed stat, and they make Greninja a nearly unstoppable force. If it accesses its Hidden Ability Protean, it can change its type according to the move it uses. With this, Greninja can gain a Same Type Attack Bonus on any strike. This is invaluable and allows for helpful strategizing.
Noivern
Noivern has a consistent stat spread, with a higher value in its Special Attack. Its biggest strength, though, comes from its Speed. This stat is much higher and lets it strike first on most occasions. As a Flying/Dragon-type, Noivern can use powerful moves like Dragon Pulse, Air Slash, and Hurricane with a Same Type Attack Bonus. These three moves are also Special attacks, which are Noivern's specialty. Its extreme vulnerability to Ice can be an issue if it does not knock out opponents in one hit, but this is often not a problem.