Observable's html templates were inspired by lit-html, but they ended up implementing their own library. I'm glad the lit-* stuff is useful to you, and really excited to see it available in cells. I'll have to try this out!
Also, have tried PureScript? e.g. [1]
One big difference to the projects you listed is that lit-html doesn't require a compiler. It's plain JS, and is fast because it uses template literals and built-in HTML parsing/cloning to associate expressions with DOM.
Without lit-html Starboard would be nowhere near as flexible or elegant. Starboard has to be completely customizable at runtime, that would probably be difficult to achieve with anything that has a build step, with lit-html it's "just Javascript" all the way down.
If you usually use a framework like React, Vue or Svelte it is still worth trying out lit-html, they are not mutually exclusive, it's simple to learn and deceptively powerful. It's great to have it on your toolbelt.