There are a lot of Key Items in this Pokémon game, here is a list of the most useful and hard to get Key Items in the game. This tells you what they do and how to get them.
|Unlockable||How to unlock|
|Magma Stone||Allows you to be able to Battle and Catch Heatran in Reversal Mountain. You can find it on Route 18 which you can only reach by entering the Hall of Fame.|
|Lunar Wing||Allows you to Battle and Catch Cresselia on the Marvelous Bridge. You can get this by going to the Strange House in the area outside of Reversal Mountain. You can only access Marvelous Bridge after you enter the Hall of Fame.|
|DNA Splicers||Allows you to merge Kyurem with Reshiram or Zekrom. You can only get this by Catching/Defeating Kyurem in the Giant Chasm for the second time. It drops it after the battle.|
|Gracedia Flower||Have a Shaymin in your party and talk to the girl nearest to Nurse Joy in the Striaton City Pokémon Center. You can only reach Striaton City after entering the Hall of Fame.|
|Permit||Allows you to go to the Nature Preserve by Skyla's Plane. The Nature Preserve has a Level 60 Shiny Haxorus and contains many rare Pokémon like Kecleon. You can get it from Professor Juniper in Nuvema Town by showing her your Pokédex when you have seen all of the Pokémon in the Unova Dex, not counting Meloetta, Keldeo, Genesect, and Victini.|
|Oval Charm||Makes eggs hatch faster. Show Professor Juniper, a complete Unova Dex, All Pokémon are caught, in Nuvema Town.|
|Shiny Charm||Makes Shiny Pokémon more common. Show Professor Juniper, not Cedric, a Complete National Pokédex in Nuvema Town..|
|Reveal Glass||Go to Abundant Shrine with Therian Landorus, and a n old man will give you this item, when you get to the wooden shrine. Use this to change Formes of Landorus, Thundurus and Tornadus.|
Hidden Grottos are hidden all over the Unova Region. The trick to finding them is to look closely at the trees in the surrounding area. Trees that hide Hidden Grottos don't have an open patch of dirt in between them, they have a dark green spot, or some other color depending on the season, instead that makes them look like they've merged together. The Hidden Grottos are not in every location in Unova but reside in the following locations: Route 2, Route 3, Route 5, Route 6, Route 7, Route 9, Route 13, Route 18, Route 22, Route 23, Floccesy Ranch, Giant Chasm Crater Forest, Lostlorn Forest, and Pinwheel Forest. How many are in each location is hard to say, but if you enter all of them you'll get a medal for the achievement.
On a side note, you can find items, mulch, or Pokémon with hidden abilities in the Hidden Grottos every day.
If you have the event Keldeo on your Pokémon White Version 2, you can teach it its' signature move, Secret Sword, by having it in your party and heading to Alder's house in Floccesy Town. Behind his house is the entrance to Pledge Grove. At the back of this sacred place is a huge rock with large gashes in it. Examine the rock to be able to teach Keldeo Secret Sword!
If you have the event Meloetta, you can get it's signature move, Relic Song. Go to Castelia and go to Narrow Street. Go to the Cafe and the guitar player will play you the song that Meloetta has forgotten. Before he plays it, Meloetta will come out of the Pokeball and dance. Meloetta will learn Relic Song. You can now turn Meloetta to Pirouette forme in battle, but it changes back after battle. You can also get the funfest mission "The Berry-Hunting Adventure!" for showing Meloetta to the guitarist.
In a building near the gym in Castelia City, you can meet with someone who will massage your Pokémon once a day. This is very helpful for Pokémon with friendship Evolutions, as massages raise a Pokémon's friendship.
The move deleter is a man in Pokémon Black and White 2 that will delete any move of your Pokémon's, TM or HM, free of charge. He is located at the Pokémon World Tournament. This can be helpful, because it is the only legitimate way to delete HM moves.
The Name Rater is a man in Castelia City near the gym that will change the name of your Pokémon free of charge. The only exceptions to this, however, is he will not change the name of any of N's Pokémon, and he will not change the name of any Pokémon that was traded to you.
At Pokestar studios north of virbank city there is a tree that you can surf in. The tree is on the right side of the movie theater and is the closest to the water.