A colorblind-friendly palette including gray and black

colorblind.R

cb <-  c("#E69F00", "#0072B2", "#009E73", 
         "#CC79A7", "#56B4E9", "#D55E00", 
         "#661100", "#F0E442", "#332288",
         "gray40", "black")

library(ggplot2)

ggplot(data.frame(x=c(rep(c(1,2,3), each=3), 4,4), y=1:length(l), color=LETTERS[1:length(l)]),
       aes(x=x, y=y, color=color)) + 
geom_point(size=10, show.legend=FALSE) +
scale_color_manual(values=cb) +
theme_bw()