Recommendations for SaaS projects to learn from?

Do you know any public repositories that are good SaaS examples? I'd like to read through them to understand how they organize things, how they structure their routes and interface with their database, what they use, etc.

My preferred tech stack for the example would be Node.js (or Deno), a simple router (like Express or Oak), and a simple templating engine (rather than something like React, which I have to learn still...). But, I'd be happy to look at other examples if you have them, too.