What Pokemon are only available in BDSP, but not in other Switch titles?

Question

List all the Pokemon where Pokemon Brilliant Diamond and Shining Pearl are the only Switch titles in which these Pokemon are obtainable. (these Pokemon are not available in all other Switch titles such as Sword, Shield, Scarlet, and Violet)

In all cases, these Pokemon are only obtainable in BD/SP after unlocking the National Dex in these games.

P.S.: All Pokemon from Gens 1 and 4 have appeared in at least two Switch titles, with:
- All Gen 1 Pokemon are available in Let's Go Pikachu and Eevee.
- All Gen 4 Pokemon (including those that are not in DP Sinnoh Dex) are available in Legends: Arceus.
- All Pokemon introduced in Gens 1 to 4 are available in BD/SP due to the Gen 4 National Dex, and most of these (not all of them) are also available in other Switch titles.

Answer 1

• Ledyba line
• Taillow line
• Skitty line
• Spinda
• Castform
• Kecleon
• Clamperl line

Source: Manually going through each Pokedex entry of Johto and Hoenn.

Out of those, the only version exclusive is Kecleon to Brilliant Diamond, so if you are only going to get one, get Brilliant Diamond.

Hope this helps!

Comments

Also note that is not possible to deposit a Spinda caught in Pokémon Brilliant Diamond or Pokémon Shining Pearl into Pokémon HOME and vice-versa. As a result, you can only transfer Spinda through Pokemon Bank.