WordPress plugin that shows current WordPress, PHP, Web Server and MySQL versions in admin footer
WordPress plugin for Disqus (2018 version)
Slurps down every stable version of every plugin in the WordPress plugin directory.
WordPress plugin for Coral
A WordPress plugin to stop users from updating plugins and themes if they're under your control.
Mailgun's Wordpress Plugin
A lean WordPress plugin boilerplate, ready for your next project.
[WordPress] A foundation for WordPress Plugin Development that aims to provide a clear and consistent guide for building your plugins.
A custom update checker for WordPress plugins. Useful if you don't want to host your project in the official WP repository, but would still like it to support automatic updates. Despite the name, it also works with themes.