Copier is described as 'modern template manager that allows you very simple features such as maintaining templates that are not even git repos, or very advanced features such as updating projects based on their templates, or applying several templates to the same project' and is an app in the OS & Utilities category. There are three alternatives to Copier for Linux, Mac and Windows. The best alternative is Yeoman, which is both free and Open Source. Other great apps like Copier are Cookiecutter (Free, Open Source) and cookiedough (Free).
Yeoman is a robust and opinionated client-side stack, comprising tools and frameworks that can help developers quickly build beautiful web applications. We take care of providing everything needed to get started without any of the normal headaches associated with a manual setup.
cookiedough is a GUI browser for cookiecutter templates. And can of course extract them. It comes with a database of around 2300 cookietemplates, grouped by category, and allows some rudimentary filtering. Very early alpha, but usable.