Special Pokémon that were specifically and selectively bred for their appearances, temperament, and/or their lineage. Most of these Pokémon are common enough, but some are rare and sought-after. All of these Pokémon are known for having recessive genes, and so cannot pass on their special characteristics if bred with a Ditto or their normal counterpart, unless an Everstone is held.
Special Pokémon occurring naturally in the wild, but seldom seen by humans. Some of them are mutations of their normal counterparts, some are the spirits of defunct Pokémon clinging to this world, some are juvenile forms of ancient Pokémon, and still some are simply Pokémon specially bred for appearances who have contaminated the wild population and sustained themselves.
Special Pokémon known to only come out during set periods of time. Scientists have found that these specimens, although looking rather like pranks played on unsuspecting trainers, are genuine, rare Pokémon mutations seemingly celebrating the beliefs and holidays of their human companions. Some theories propose that they are Arceus' attempt at honoring human customs with its own offerings.
Odd Pokémon that can only be encountered at the World Tower. They can only be caught on the same floor as the trainer who uses them. While they can breed just like their normal counterparts, they always produce children of the other parent and cannot pass on egg moves, just like Ditto.
Very strange Pokémon that seem to have come from other dimensions. They act strangely compared to normal members of their species, have remarkably unique patterns, almost never show common species traits, and often don't share the same level of understanding human speech as their species commonly do. They always have only one nature, and are rejected from any kind of Poké Ball, even Master Balls. Though there is a rumor about something called "Rift Balls" that can only catch these Pokémon…