Even though colorblind people can recognize a wide range of colors, it might be hard to differentiate between certain colors.
RColorBrewer
provides colorblind-friendly palettes:
library(RColorBrewer)
display.brewer.all(colorblindFriendly = T)
The Color Universal Design from the University of Tokyo proposes the following palettes:
#palette using grey
cbPalette <- c("#999999", "#E69F00", "#56B4E9", "#009E73", "#F0E442", "#0072B2", "#D55E00", "#CC79A7")
#palette using black
cbbPalette <- c("#000000", "#E69F00", "#56B4E9", "#009E73", "#F0E442", "#0072B2", "#D55E00", "#CC79A7")