Ask HN: How to find production-ready open source projects to learn from?

I have been trying to find open source production-use projects to learn backend architecture. I did find a analytics startup called posthog, where I learnt about django use in a real world product. Is there a website which lists these out by lang and domain (backend api, system application, frontend etc.). I did try github explore and search, it's not really useful. And google just shows beginner level blogs about these.