Relevant: https://github.com/commaai/body#comma-body (I'm aware that the Comma Body just uses wheels, and thus differs from Upkie in that Upkie claims to support uneven terrains)

I had no idea about https://github.com/stephane-caron/awesome-open-source-robots -- there's one of those for everything, I guess (and are also a just stunningly terrible way to distribute collections of links, IMHO, since creating Wikipedia pages is free and those can be edited by anyone with an account, versus the "open PR and pray" model of GitHub)