Like a dock and menu bar? Tint2 for the dock. I believe Cairo dock is also an option. Polybar for the top bar.

Keep in mind that achieving specific looks often requires tons of time in configuration and hunting down specific tools or fixes. For instance, rounded corners might be a feature of your WM, your compositor or a combination of both. Some stuff will only work correctly if you’re using the right DE while others will only work if you use no DE at all.

Thanks, not heard of Tint2 or Polybar before, will check them out.

You may be interested in elementary os[1]. All their stuff is oss, though I don't know how easy it would be to use it on ubuntu.

1. https://elementary.io/

It’s just add a ppa (ppa:elementary-os/stable) and sudo apt-get install elementary-desktop.

Do note that the stable PPA does not have releases for 20.04 (focal). You'll have to use the daily to try it out on 20.04 based distributions.