Cam Harris, who fabricated viral stories about Hillary Clinton, did so while living in the home of his boss, a Republican member of the Maryland legislature.
Source: Major Fake News Operation Tracked Back to Republican Operative
Also see “Man behind ‘alt right’ fake news sites is registered Democrat”
For all of these, making money is usually the motivation. Secondarily, they may be playing dirty politics, but as the 2nd link illustrates, even that meme is messed up when fake news creators cross party lines. Fake news can be very profitable!