Submitting multiple apps with only cosmetic differences, or an app that duplicates functionality already common on the Store without adding real value, falls under this guideline.
Most commonly triggered by template-generated apps (the same shell with a different logo/color), or by resubmitting a rejected app under a new bundle ID instead of fixing the underlying issue.
"Your app duplicates the content and functionality of other apps submitted to the App Store, which is considered a form of spam."