A quick search of the market did not turn up anything.
I need a content filter based on categories. What is needed is a page where there is a list of all the categories on the site, broken down by modules to make it more manageable, with a checkbox so that a member can "opt-out" seeing content that is listed with certain categories. For example, a member could opt out of seeing any content with the category of religion or politics. Then when they go to view the list of blog posts, or other content, they won't see the blog posts with the category of religion or politics. I also realise this module will require core changes but it is a feature that is desperately needed in Dolphin.