Use this tag for questions related to the ggpattern package. The ggpattern package is an extension package for {ggplot2} which "provides geoms filled with various patterns".
The ggpattern package provides
ggplot2 geoms filled with various patterns. Includes a patterned version of every ggplot2 geom that has a region that can be filled with a pattern. Provides a suite of ggplot2 aesthetics and scales for controlling pattern appearances. Supports over a dozen builtin patterns (every pattern implemented by {gridpattern}) as well as allowing custom user-defined patterns.
An overview and introduction to theggpattern package can be found on the package website