Empty iOS App Folders in an Instant
Reset your home screen layout hidden in Settings > General > Reset. This will reset your first home screen to factory settings, with all additional home screens displaying your third party apps in alphabetical order, which is a nice fringe benefit in its own right.
Unfortunately, this is a bit of a nuclear option. You can't pick and choose which folders are removed and where apps are placed. However, if you want to go back to the pre-folder era of iOS, this is by far the quickest way to get there. This also restores icons on your iOS device that mysteriously disappear