The Comprehensive R Archive Network, or CRAN.

Go to 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.