This is the Bulbapedia walkthrough for Pokémon Brilliant Diamond and Shining Pearl.
These pages follow the remade Nintendo Switch iteration, not Pokémon Diamond and Pearl. The guide for those games can be found here.
Grand Underground
At this point in your journey you can access Pokémon Hideaways that were previously locked by entering the Grand Underground from Celestic Town.
These two caves are notable for their Ghost, Psychic, and Ice-type Pokémon.
The Icy Cave becomes particularly rewarding after earning the Icicle Badge later in the game.
Icy Cave
Icy Cave is a frozen biome with very sparse initial encounters.
Only Buneary can be found from the start, and Bronzor unlocks after obtaining TM96 (Strength).
After earning the Icicle Badge, the cave opens up significantly with Sneasel, Snover, and Mr. Mime.
Sneasel is a Dark/Ice-type Pokémon that evolves into Weavile when leveled up at night while holding a Razor Claw.
Snover is a Grass/Ice-type Pokémon that evolves into Abomasnow at Lv. 40.
Stargleam Cavern
Stargleam Cavern is the large cavern version of Dazzling Cave, featuring the same Psychic and Ghost-type Pokémon on a grander scale.
Gastly can be caught here from the start, and Misdreavus appears as a Pokémon Shining Pearl-exclusive.
Kadabra and Girafarig become available after obtaining TM97 (Defog).
