the mundane, myth, folklore, superstitions, and how it intersects to the point of inseparability. a commonality so deeply ingrained in the pokemon world's society for the most obvious of reasons, permeating daily life regardless of how small its echoes are. like what defines a haunting or the breed of a boogeyman? ask the question: what came before the pokedex entry had it down to a comforting science? how does this expand into urban legend? even cryptozoology? for example, take a look at marshadow: a pokemon that's been so unseen that the truth of its existence is openly doubted. the same can be said for mew. there's no way there isn't a subculture dedicated to overshadowing these doubts, even if a few bored souls take advantage of the digital age in doing so with the grainy (NOT CLICKBAIT!) footage uploaded for the world to pick or rip apart.
i think i've mentioned it before how a suspected poltchageist (hah) could be discredited by skeptics as something else, be it average phenomenon to a ghost-type rather than the entirely supernatural. maybe your recent string of misfortune is simply coincidence instead of a curse. but does it make ghost-types any less dangerous? is it enough to discourage people from the practice of protecting themselves? what differentiates a group of mismagius from a walpurgisnacht? aren't houndoom still hellhounds no matter how much its dex entry and a pokeball try to file down their horns? what about grounds both revered and feared because of the fairy-types treading them? would you take your chances carelessly blurring the lines? or would you prefer trying to ward them off with talismans, rosaries, and even the power of prayer?
and can you imagine the types of cautionary tales parents would tell their children to get them to behave, too? like irl, hypno's lullaby may be a creepypasta, but don't you think it merits having a place in the reality of the series? "stay up too late past your bedtime and a hypno might come and snatch you away." tales spun to snuff out their curiosity towards a forest, body of water, or a cave lest they be gobbled up by something sinister lying in wait for them. the young and the old alike both harboring a childish, naive fear of sharpedo-infested waters despite its their home, people being ostracized for owning certain pokemon surrounded by stigma…
once upon an accusation of witchcraft, the hysteria behind sicknesses running rampant, chants, divination, omens, silvers, tricks against tricksters… the list goes on and varies from region to region, cultures to cultures, species to species. even with the new-aged luxury of being able to take modern approaches, the remains of tradition extend like ancient catacombs across the earth.