There are two very useful R packages which are essential for heavy R users: dplyr and readr. The first one is to manipulate data in a more intuitive manner, and the second one is for reading csv files with a bit more options than the native R packages.
This is a nice list with a lot of resources for those of us who are learning English, ranging from dictionaries to thesauri.
I came to notice the work of Emily Carrol. Her work is just amazing!
My favourite: His face all red.