A lot of color pickers present available colors as circles of that color. When you do this, bigger circles are better. The bigger the circle the easier it is for me to tell the colors apart. Including the color name does help a bit but I honestly prefer just being able to see what the color is. I've attached images of color pickers from two calendar apps. On the one with small circles and color names, most of the colors look the same to me, and the names don't mean much.