This is not an addon because each app will have different needs and requirements. Instead, this guide is intended to demonstrate best practices so teams can build the components that are right for their project. Additionally, an addon requires maintenance, which is a non-negligible set of work on its own.
It's likely that your favorite component pattern isn't here yet because it hasn't been added yet. Or it's a carousel and those will never be here because they should never be used.
Thanks for catching it! Please file an issue here: https://github.com/MelSumner/ember-component-patterns/issues.