"Articles on Statistical Computing - R" from the Social Science Computing Cooperative, at the University of Wisconsin-Madison
"Advanced R," by Hadley Wickham
"Data Transformation with dplyr:: Cheat Sheet"
"Getting Started in Data Analysis Using Stata and R," by Oscar Torres-Reyna, Princeton University
"Quick-R - 'Accessing the Power of R'"
"R for Data Science," by Garrett Grolemund and Hadley Wickham
"R - "Quick List of Useful R Packages"
"RStudio Cheat Sheets"
"R for Stata Users," by Matthieu Gomez, Princeton University
"R Graphics Cookbook," by Winston Chang
"R Markdown Cookbook," by Yihui Xie, Christopher Dervieux, and Emily Riderer
"Resources to Help You Learn and Use R," from UCLA's Academic Technology Services
"Teaching R in a Kinder, Gentler, More Effective Manner: Use Base-R, Not the Tidyverse," by Norm Matloff
"Tidyverse - R Packages for Data Science," by Hadley Wickham
"The Tidyverse Style Guide," by Hadley Wickham
"Using R to Analyse Key UK Surveys," from the UK Data Service (.pdf)