WP Hacks Admin Notices provides a backend and developer friendly options, for adding conditional admin notices to your site by user, post, terms, metadata, status and post type, and featured image. Great for gentle reminders to authors and editors, E.G. Don't publish publish this post until you add an image, or This post is sponsored Content, and must be approved before publication.
Please read the TODO list at the top of the plugin file. This plugin is under heavy active development.