Creepy Pastas: not gonna be added to the main site. But when the forum is done that would be a good place for people to post and discuss them.
Betas: not really sure what you mean, do you mean like fakemon and such? Again, might be a good fit for the forum.
Secrets: something like this would be a good fit for the Pokedex pages. I've been thinking about adding more general information about Pokemon.