ggplot2
An implementation of the Grammar of Graphics in R
... for plotting.
In most cases using ggplot2 starts with supplying a dataset and aesthetic mapping (with aes()); adding on layers (like geom_point() or geom_histogram()), scales (like scale_colour_brewer()), and faceting specifications (like facet_wrap()); and finally, coordinating systems. ggplot2 has a rich ecosystem of community-maintained extensions for those looking for more innovation.
ggplot2 is a part of the tidyverse, an ecosystem of R packages designed for data science.