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.
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
Core - https://cdn.jsdelivr.net/gh/lit/dist@2/core/lit-core.min.js
All - https://cdn.jsdelivr.net/gh/lit/dist@2/all/lit-all.min.js