"Top 40 Bad Books" is actually a collection of 40 short commentaries about bad books, from which, amazingly, I have been able to extract precisely 40 books that received a specific mention (but admittedly varying widely in their perceived degree of badness). You'll have to at least skim the commentaries to find out why a particular book was called bad (they are usually only a few paragraphs long).
The remaining 24 books are from a variety of sources, mostly from 'the complete review' website (which itself links to multiple reviews). I've included a few of my own 'favourites' (I never got beyond a few pages).
Please check an item only if you have made it right to the end. And you have my profoundest admiration if you managed that with "Tarantula".