At least for the design system, the answer is yes. The US Government Design System: https://designsystem.digital.gov/

Don't have the URL handy, but California has an amazing design system as well.

I'm sure there might be because several years ago the U.S. created the U.S. Digital Service with the premise being recruiting professionals (yeah mostly from corporate but not only) to spend time in the government and help modernize many of its aspects and offerings...for the benefit of the citizens, etc. Here's one example of their playbooks: https://playbook.cio.gov/

...While not exactly like the Singapore page linked in this post, alot of the intent with the USDS - as i understand it - is alos to be quite transparent with the hope of any other government agencies/orgs such as state/province level, city level, etc. benefiting from their ideas and hopefully broadening the benefit at all levels. Here is the main site, but of course (as the above playbook link denotes), there are plenty of other related sites that might help better answer your question: https://www.usds.gov/mission