Doctor Who easily
has the best novel range of any sci-fi franchise. The novelizations are generally mediocre with a few classics (Ben Aaronovitch's Remembrance of the Daleks is top dollar!) but the VNAs and EDAs are outstanding ranges.
If we're talking bad Doctor Who books, The Eight Doctors is utter jizz-covered shit. Terrance Dicks is a sacred cow that should be put down.