There’s a notebook for click-to-copy buttons: https://observablehq.com/@mbostock/copier
For Observable imports, we’re thinking about how to make imports easier to discover and incorporate into your notebook. I’d rather solve that at the platform level if possible than require people to add instructions to every notebook that’s intended for importing. Feel free to chime in on this issue: https://github.com/observablehq/feedback/issues/31