Kottke serves up a number of lists:

http://kottke.org/15/11/best-fiction-of-2015

Among those not already linked upthread or sibling:

Tyler Cowen, fiction and non-fiction:

http://marginalrevolution.com/marginalrevolution/2015/11/bes...

http://marginalrevolution.com/marginalrevolution/2015/11/bes...

Buzzfeed Fiction:

http://www.buzzfeed.com/isaacfitzgerald/books-we-loved-in-20...