- How to get Glaceon and Leafeon
In order to evolve an Eevee into a Glaceon or Leafeon, stand next to Ice Rock or Moss Rock while you are leveling it up. The Ice Rock can be found first. It is located deep in the Frost Cavern. Moss Rock can be found closer at the end of the quest - defeat the Elite Four. You will find it on Route 20. It is between Snowbelle City and the Pokemon Village. When you enter the area from Snowbelle, you will immediately see it.
- How to get the Legendary Birds
Once you have defeated the Elite Four, one of the three Legendary Birds that are in the original Pokemon Red and Blue will begin showing up throughout Kalos. The bird that will appear depends on who your starter is. For example, if you chose Froakie, you will get Moltres. If you chose Chespin, you will get Articuno. If you chose Fennekin, you will get Zapdos. Once you get one of the birds, check the entry of it in your Coastal Kalos Pokedex. There it will show you the bird's current location. You will have to walk; you cannot fly to the location and challenge the bird again. If you flee several times, the bird will eventually go back to Sea Spirit's Den, which will allow you to catch it.
- How to get Mewtwo
Beat the Elite Four, and then return to Pokemon Village. Go a cross a small stream on the west side using the Surf HM to get to a cave opening. Mewtwo will be inside immediately once you get into the cave. A person will block the cave entrance, but will disappear once you have defeated the Elite Four. Mewtwo will be Level 70. A Master Ball will capture him. Once you’ve captured him, you will also get a special stone. This will activate Mewtwo's Mega Evolution.
- How to get Pikachu
You can get Pikachu in Route 3, right after the forest. It will be in small grass patches. Getting him will allow you special attacks and speed stats that give him an early advantage. He can paralyze Pokemon that come in contact with him. Pikachu he will also levels up very fast and early in the game.
- How to get Sylveon
In order to get Sylveon - max out all three stats (Affection, Fullness, and Enjoyment). From there an Eevee to evolve it into a Sylveon. Once you max out all stats for an Eevee, you will have to keep petting and playing the mini-games. It will take you exactly one hour to max out all the stats for the Eevee. Important - Make sure you teach the Eevee a Fairy move before you level it to Sylveon.
- How to get Zygarde
Beat Elite Four, and then return to Terminus Cave. Located just off Route 18. Terminus Cave is the longest dungeons in Pokemon X/Y. Make sure you have lots of healing items and strong Pokemon before you even think of entering it. Zygarde is found at lowest level of the cave. It is only unlocked after defeating Elite Four. A few rare items are in the lowest level of cave. You’re going to need to use Master Ball to capture him. If you don’t the battle will be long and require a lot of Ultra Balls.