Here's one "dark pattern": Writing about a site and hiding the clickable link deep within the text of the post, in a way that the text of the link doesn't indicate that it actually takes you to the site, in the middle of a jungle of other links that take you to various other articles on the same blog.
I wouldn't call it dark pattern but rather an anti-pattern or just a plain-old mistake/oversight. Dark pattern implies the website gains something by misleading the user. In this case, the guy actually loses hits/viewer to the main website he is talking about. So it is more of a usability oversight than usability insidiousness.
