Bryan Shalloway does a search:
TLDR: funspotr provides helpers for spotting the functions and packages in R and Rmarkdown files and associated github repositories. See Examples for catalogues of the functions/packages used in posts by Julia Silge, David Robinson, and others.
This is an interesting project. I’d imagine that with enough different code bases, you could develop a programming profile and possibly understand people’s strengths on a variety of characteristics like which functions they use, what they use given alternatives (e.g., “functional-friendly” map versus the *apply series versus loops), and how familiar they are with certain packages. I could see this being an advanced technique for learning what you should learn next: you obviously have familiarity with packages A, B, and C but it appears you don’t know about E or K and you might learn them to replace some of the work you’re doing with C.