From Bulbapedia, the community-driven Pokémon encyclopedia.
Version-exclusive Pokémon are Pokémon that are only found in one or two games in a single generation, to encourage trading between multiple players. For instance, in the original Pokémon Red, Bellsprout was absent but appeared in Pokémon Green (Pokémon Blue outside Japan). Version-exclusive Pokémon usually complement each other in design, type, as well as location of appearance in the wild.
It is typical for several evolutionary families of Pokémon to be version exclusives in the first two games of a generation, and then, in the third version, some version-exclusives from the first two games will be obtainable, while others while not, and in the third version, some Pokémon will be unobtainable that were obtainable in both of the first two games. For example, the Weedle and Koffing families were obtainable in both Pokémon Red and Blue, but unobtainable in Pokémon Yellow.
Below is a list of Pokémon exclusive to games. This list does not take note of Pokémon exclusive between Generation III Kanto and Hoenn games, simply because there are too many Pokémon that are native to each individual region to list; a better indicator of those Pokémon which are missing from each region would be the Kanto Pokédex and Hoenn Pokédex. However, even this does not take Generation II Pokémon into account, since the vast majority thereof is only listed in the National Pokédex of those games. Furthermore, a list of Pokémon missing from the Generation III GameCube games, Pokémon Colosseum and Pokémon XD, is far too long to be included in this context.
Take note that the Pokémon listed below are from that particular game, and will need to be traded from a game within the same generation that does not list them. Therefore, Pokémon obtainable in Generation II by trading with Generation I, Pokémon obtainable in Generation IV by utilizing GBA games, legendary Pokémon and starter Pokémon and Pokémon obtained from attending promotional events, are all excluded from the following list.
It is of relevant note that in Pokémon Diamond and Pearl, most of the version exclusives of the Generation III games can be caught in the wild by inserting one of the GBA games into the DS. In Pokémon XD, the seven Emerald-absent Pokémon are all obtainable, thus eliminating the need in trading with either Pokémon Ruby or Pokémon Sapphire.
Please note that the Japanese Blue Version does not have the same Pokémon distribution as the English Blue Version. The English Blue's Pokémon distribution is in fact the same as that of the Japanese Green. Listed below under the "Blue" header is the Japanese Blue.
Please note that Phanpy, Donphan, Teddiursa, and Ursaring are available in the opposite paired version in Japan that they are internationally, with the first two in the Japanese Gold and the latter two in the Japanese Silver. However, this change does not occur in HeartGold and SoulSilver's international release.
- The following are only found in Pokémon Emerald, once the National Pokédex is completed: Hoothoot, Spinarak, Mareep, Aipom, Sunkern, Snubbull, Stantler, Remoraid, Octillery, Pineco, Teddiursa, Ledyba, Houndour, Miltank, Shuckle, Ditto, Sudowoodo and Smeargle. Notably, most of these Pokémon cannot be found in Pokémon FireRed and LeafGreen.
- After mixing records with a player from a different game, Lotad, Seedot and Surskit can be found swarming somewhere in Pokémon Ruby, Sapphire, and Emerald respectively. This event will not occur until it is announced on TV.
Pokémon Mystery Dungeon
As trading is not possible between these games, the listed Pokémon will appear in the wild only when a rescue mission involving the Pokémon is completed. This requires a Wonder Mail Code from the alternate version, in which the Pokémon is normally found.