There are many packages in R.
On the one hand, it is difficult to orient yourself among all those packages. On the other, it is impossible that you can learn how to use all of them.
So it becomes handy to have a sort of classification of the most useful R packages.
In this article, we bring a couple of links and other resources (such as books, online courses(try R, code academy, coursera etc..)) where to find such packages and start practicing.
The resources are chosen in order to create a complete reference of R packages but at the same time bring to the reader only the most useful ones without unnecessary indications
For each package, a small description indicates the packages features and what the package is supposed to be used for.
Some useful links on R packages are the following
http://blog.yhat.com/posts/10-R-packages-I-wish-I-knew-about-earlier.html
https://support.rstudio.com/hc/en-us/articles/201057987-Quick-list-of-useful-R-packages
https://www.analyticsvidhya.com/blog/2015/08/list-r-packages-data-analysis/
https://www.content-loop.com/my-25-most-useful-r-packages/
https://www.r-bloggers.com/the-50-most-used-r-packages/
There are many other resources you can find even more packages such as the CRAN where the packages are listed by name
https://cran.r-project.org/web/packages/available_packages_by_name.html but there is given no description of what each package can do.