CMB2 is a developer's toolkit for building metaboxes, custom fields, and forms for WordPress that will blow your mind.
Redux is a simple, truly extensible options framework for WordPress themes and plugins!
A Simple and Lightweight WordPress Option Framework for Themes and Plugins
~ Lightweight, Flexible & Rapid WP Development Framework ~
WP Custom Fields is an options, metabox and customizer framework for WordPress aimed at speeding-up plug-in and theme development.
Create custom fields with simple and easy to use WordPress meta box framework.
Simple, Lightweight & Flexible WordPress Settings Framework
A Composer package that provides metabox orchestration for WordPress.
A PHP class that facilitates the creation of custom WordPress metaboxes
Clone Of CodeStar but with more powerfull and reliable
A WordPress plugin framework.
A WordPress plugin that adds metabox options framework for WordPress themes and plugins.
Ζεύς — Olympus Zeus is a framework which allows you to make all your WordPress plugins and themes developments easier and efficient.
WordPress Think Framework is a developer-oriented library that gives you the ability to quickly and easily create incredible websites with WordPress. This is an extensible framework for developing Wor...
Provides a compatible solution for some personalized themes that require custom meta boxes for WordPress.
A Custom metabox framework for WordPress to quickly generate metaboxes
Extending Butterbean, a neat little post meta framework by @justintadlock, with custom Settings and Controls
Just drop the admin folder into your custom WP theme and include the init.php file from your function.php, and you have access to a full range of admin option fields and metaboxes.