Especially books in genres where the norm is very short books—like intermediate-grades kids' books (Goosebumps, Boxcar Children, Animorphs, Nancy Drew, The Baby

Especially books in genres where the norm is very short books—like intermediate-grades kids' books (Goosebumps, Boxcar Children, Animorphs, Nancy Drew, The Baby-Sitters Club) or romance novels. Bonus points if you can re-use the same two or three chapter-by-chapter beat-for-beat outlines over and over. Of course, that quality also makes those sort of books the easiest to have ghost-written.