I think we’ve linked to this before, but it’s worth sharing again as people have continued to add implementations. The conceit:
While most "todo" demos provide an excellent cursory glance at a framework's capabilities, they typically don't convey the knowledge & perspective required to actually build real applications with it.
RealWorld solves this by allowing you to choose any frontend (React, Angular 2, & more) and any backend (Node, Django, & more) and see how they power a real world, beautifully designed fullstack app called "Conduit".
It’s so cool that you can plug and play different front ends (13 so far) and back ends (32!) and the app will continue to work because they all conform to the same API.