Not requiring NPM was one of my original requirements for anything on this list. All of these libraries should be available from HTML directly -- let me know or make a PR if that isn't the case.
That's because the vast majority of the JS ecosystem installs libraries via npm.
We can't really put all of the different ways to use Lit on the front page, but we document how to use Lit from a CDN right on the getting started page: https://lit.dev/docs/getting-started/#use-bundles