I think the answer is this doesn’t exist. Your best bet is to search here on Discourse for specific topics in the hope to find something like this:
but this isn’t very widespread. Another avenue is GitHub organizations, but again this is topic dependent. I agree with Julio that in most cases your best bet is probably sticking a few keywords into JuliaHub and see what comes up for code and doc search - at least there it’s relatively easy to see how popular/well maintained (based on GitHub stars/commits) packages are.