The Comprehensive R Archive Network, or CRAN.
Go to https://cran.r-project.org/ and click on to Task Views on the left hand menu. This will take you to the CRAN Task Views. This is where you will find a huge collection of R packages organized by tasks. For example Finance, or Graphics, or Econometrics. This list and sub-lists are huge. Over 11,000. It’s a project that has been going on since 1992, so it’s a very good library to delve into.