The stickylabeller package helps you label the facets in your ggplot2 plots. If you know how to use the glue package, you know how to use stickylabeller! Some stand-out features include the ability to automatically number/letter your facets for use in papers and reports, as well as the ability to easily include summary statistics in your facet labels.

A stickylabeller plot, including multiple faceting variables and automatic numbering

You can install stickylabeller, learn how to use it and file any issues you have with it on GitHub!