Add Ons Extensions, sister plugins, and other bits of code to customize your implementation and help you integrate with 3rd party services or other plugins. All open source and available for free under the GPL v2 license.
These official PMPro plugins are available in the WordPress repository and can be installed through Plugins --> Add New.
These official PMPro plugins integrate with specific third-party tools and software.
These official PMPro plugins must be downloaded from GitHub and installed through Plugins » Add New » Upload, then activated. These plugins cannot be automatically updated and may require more developer input.
These are bits of code that generally must be added to your active theme's functions.php file or included in a custom plugin. Most gists require customization and are recommended for developers only.