What I think would be fun sometime would be to do the color wheel - any shades of a particular color - either solids or prints that read as one color
Red and Burgundy and Pink
Red Orange and Rust and Peach
Orange
Yellow Orange
Yellow and Gold
Yellow Green - Olive
Green
Blue Green -Turquoise - Aqua
Blue - Navy - baby blue
Violet Blue
Purple
Violet Red
How about grays ? I have very few of them in my stash.