The Pokemon Audino's design was created for the Pokemon Anime first and foremost. Artist Ken Sugimori stated he wanted a Pokémon that would look good alongside the series' Nurse Joy just like Chansey did, as he knew the Anime would go the same route as Black and White, and would feature an entirely new roster of Pokemon.

According to an interview with Ken Sugimori, Deino and it's evolutions, Zweilous and Hydreigon, were originally desinged to be cyborg tanks, but the idea was scrapped, then revived to look more like the mythical Yamata no Orochi.

Sugimori stated in the interview, "Deino, Zweilous, Hydreigon. At first, these incorporated an army tank motif, and the marks that look like a conveyor belt on the upper part of Zweilous's legs are the remnants of that. Initially, they didn't work as designs and were basically 'put to sleep', however, a three-stage powerful Dragon-type family was ordered and they were resurrected."

The game contains unused hidden abilities for certain Pokemon. They include a Zapdos with Lighting Rod, the Snivy family with the ability Contrary, and a Chandelure with Shadow Tag.

In the beta version, when buying items at a Pokémon Center, the part of the screen where the player can be seen is rotated.

Darumaka is designed after a Daruma doll, both having similar markings and neither being able to be laid out on their sides.

Game Freak has its own building in Castelia City. They appear on floor 22, the same floor as in their real life office in Carrot Tower, Tokyo, Japan.

According to game scenario author Toshinobu Matsumiya, Hilbert and Hilda were initially visualized to be 16 years old.

During certain occasions, the spirit of a deceased young girl will be standing on the bridge, and will disappear if the player walks towards her. An old lady in the gate to the east of the bridge will explain that the young girl used to play around the area with an Abra before the bridge was built. In the sequels, the girl will also appear in Strange House where she will refer to Abra and the bridge before telling the player to return the Lunar Wing there, which will trigger a battle with Cresselia.

The idea of having two rivals instead of one came from early concepts for the Pokemon series that went unused until Black & White.

Fans believe a number of areas in the game include music that sounds similar to music in Mother 3, such as Pokemon's "N's Farewell" and Mother 3's "Love Theme," and Pokemon's "Surf Theme" sounding like Mother 3's "The Green Train's Fun Too!"

None of the songs in the game are confirmed to be inspired by the Mother series.

There are unused 3D models for both Dialga and Palkia from the title screen of Diamond & Pearl. There are also logos for Pokemon Diamond and Pearl in the data, probably because Black and White were built on top of those games.

Genesect's backstory is similar to Mewtwo's. Both were created by villainous teams in at least one canon (Team Rocket for Metwto and Team Plasma Genesect), and genetically engineered and enhanced to be more powerful.

Prime numbers had a significant role in the composition of N's battle theme. Though there is little evidence to suggest this in-game, N is actually a mathematical genius. It can also be said that he sees the world in a 'black and white' fashion, using formulas to make sense of it.
Composer and director Junichi Masuda frequently references this in N's battle theme with the use of prime numbers, and even more so with the addition of sounds like a clock ticking in N's final battle theme.

The GTS has a filter to prevent Pokémon with inappropriate nicknames from being traded. However this prevented Pokémon, such as Cofagrigus, from being traded without nicknaming it because their name contains a keyword. This has been mostly fixed but some Pokémon, such as Nosepass, are still unable to be traded without a nickname.

On Route 10 in the original Pokémon Red and Pokémon Blue, Picnicker Carol gives a description of a chunky, pink Pokemon with a floral pattern. This description is what Munna was based on.

The Sword of Justice legendaries are inspired by the Three Musketeers.
Cobalion, Terrakion, and Virizion are based on Athos, Porthos, and Aramis respectively, while Keldeo is similar to the youngest Musketeer, d'Artagnan.

There is an unused stone in the game's code called the God Stone. A gray recolor of the Light Stone/Dark Stone sprite, with the description "A phantom stone."

In the Café Warehouse in Nacrene city, by looking at middle or right tile of the door, pressing A will show a message saying: "It looks like a cabinet full of Pokémon goods."

TM67 Retaliate & TM94 Rock Smash both have a sprite oversight where the TM Sprite does not match the Type in the HUD.
Retaliate is a Normal move but is shown as a Dark Type in the Sprite.
Rock Smash is a Fighting move but is shown as a Rock Type in the Sprite.

Game Freak spent a year and a half developing the story and characters for Pokemon Black & White.