Rare Pokémon guide

Answer 1

Sorry if I'm misunderstanding you by rare. But here's some nice Pokemon that are hard to get in Black and White.

Volcarona- At the bottom of Relic castle after beating the Elite Four. Found at level 70.

Kyrusem- Found in the very center of the Giant Chasm at level 75 (I'm pretty sure, maybe 70)

Tornadus- (Black only) Head towards Route 10, and you will be informed that there is strange storm in Route 7. Head there and keep walking til you walk past a house just east of Celestial Tower. An old lady well bring you inside, heal you and tell you a story. After that go into the tall grass until you find him. He's like Mesprit and Cresselia in Diamond, so you have to chase him down. Sometimes in the gates, the billboard will tell you where the storm is. Found at level 40.

Thundurus- (White Only) Same as Tornadus

Landorus- Take both Tornadus and Thundurus to the Abundant Shrine. In the very center there is a shrine. Go up to the shrine and Landorus will come to battle you at level 70.

Cobalion- At the very top of Mistralton Cave in a room called the Guidance Chamber. He's pretty easy to find. He fights you at level 42.

Terrakion- In Victory Road near the exit. Requires strength. He fights you at level 42

Virizion- In Pinwheel Forest in the Eastern-most area called Rumination Field. Level 42.

Musharna- The basement of Dreamyard only on Fridays. Level 50.