f(x) Meta Box is a single class to create complex meta boxes design using tabs. it comes with several helper functions to create input, textarea, tabs, file/image upload, radio, select, visual editor, etc. It also comes with helper function to validate the data.
In the download zip file there’s also a plugin example where you can see how to implement f(x) Meta Box in your plugin.
This class design is highly inspired by Butter Bean Plugin.