here's my facebook filters. I don't really do this systematically, I just use the ublock element picker until I'm happy. I think you probably want the trending topics one.
! 7/5/2016, 11:08:51 AM https://www.facebook.com/
www.facebook.com###pagelet_trending_tags_and_topics > ._5mym > ._5spf._2sns
! 7/5/2016, 11:09:01 AM https://www.facebook.com/
www.facebook.com###u_jsonp_3_0
! 7/5/2016, 11:09:09 AM https://www.facebook.com/
www.facebook.com###u_jsonp_3_1
! 7/5/2016, 11:09:13 AM https://www.facebook.com/
www.facebook.com###rightCol > ._5v6d._5rzs > ._64a > div:nth-of-type(2)
! 7/5/2016, 11:09:23 AM https://www.facebook.com/
www.facebook.com###rightCol
I'd like to mention News Feed Eradicator here - not only does what its name implies, but it adds a motivational quote in the empty space. The quotes are usually about goals, procrastination, etc and it's saved me a lot of (potentially) wasted time.
