geom_abline : Add regression lines geom_segment : Add a line segment Infos This tutorial describes how to add one or more straight lines to a graph generated using R software and ggplot2 package. The R functions below can be used : geom_hline() for horizontal lines geom_abline() ...
packageDetails("ggplot2") to find out more. packagefinder comes with an add-in for RStudio that allows you to use the packagefinder functionality through a graphical interface. Check the packagefinder cheat sheet A bit more into the details: What is packagefinder? How does it benefit me?