I know someone already proposed a filter to show only favourites tags. But as explained in one of the answers,
The reason this cannot ever really be viable is mainly due to caching. If you take a look at how Interesting/Ignored tags are currently implemented, it is actually a very interesting illusion. Every time you refresh, you are getting the same exact page as everyone else. You get a list of questions, and that is pretty much it. All of the interesting/ignored functions are cleverly hidden in Javascript/CSS. On each refresh, the Javascript goes through and marks tags interesting/ignored, and then CSS properly styles them as such.
I personnally don't care(and i'm sure i'm not the only one) about the questions that are not about my favourite tags. Not at all. What about a single tag in the ignore section that ignores all the tags that are not in the favourites ?
Something like like
Right now, correct me if i'm wrong, but the only way of recreating this is by adding every tags (+- 35 000) to the ignore list.