devtools::install_github("dill/emoGG")
library(emoGG)
#you have to look up the code for the emoji you want
emoji_search("bear")
830   bear 1f43b     animal
831   bear 1f43b     nature
832   bear 1f43b       wild

ggplot(iris, aes(Sepal.Length, Sepal.Width, color = Species)) +
  geom_emoji(emoji="1f337")