These are authors whose books appear to be somewhat padded with material that may violate Amazon's Kindle Direct Publishing guidelines for inclusion in the Kindle Unlimited and Kindle Owners Lending Library programs. I have not confirmed all of them. Some may have already been removed as of 8 June 2018; some may have brought their books into compliance with current Amazon Terms of Service.
Most of the books in my personal collection are historical romance, with some of the stuffed books/stories being paranormal and/or contemporary. Some of the most notorious "stuffers" appear to be writers* of contemporary "new adult" romances. (*It's believed that many of the filler stories are written by ghost writers from fiverr and other sites.)
Alexis Angel (aka Lana Hartley)
LA Books (publisher? author? not sure)
Chance Carter (3 June 2018, some books may have been pulled from Amazon; 4 June 2018, appear to have been reinstated. 8 June 2018 appears to have been removed completely)
Annabel Hunter (may also be Alexa/Annabel Blair)
Christine M. Styles (aka North Andrews. Sarah Marquez)
Keith Taylor, aka Aya Fukunishi