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According to the data mined by BeyondTheBoxscore.com, Clayton Richard's fastball has more average horizontal movement than any other starting pitcher who pitched in 2012. It averaged 10.05 inches of horizontal movement. There are other pitchers with a "filthier" fastball (defined as being able to more whiffs and outs with the pitch), but because of that horizontal movement, we can claim that our guy is a little filthy.
Similarly, Nick Vincent has a pitch that tops the charts in average horizontal movement. His cutter averaged more horizontal movement than any other pitcher in the majors in 2012 with 3.93 inches of movement. Like Richard, it isn't the best at getting outs and whiffs, so it's not the "filthiest" but it ain't clean either.
For the leaders in all the pitch categories, check out the article on their site. It also has links to some other relevant articles on the subject of PitchFX data.