Do you know what these are? They’re those little prism toys you can get in Cracker Jacks or as a party favor at a children’s birthday party. I got the lady bug at a quilt show, but the megaphone was from a girl scout carnival.
What you do is put all the fabrics you are thinking of choosing into a stack (bolts work really well) then step back and use this little toy as a kaleidoscope. If any one fabric stands out, remove it and start again. Keep this up until you have the fabrics you need and they make a continuous kaleidoscope pattern where no one color or fabric stands out by itself.