I have bought the clear plastic boxes with small compartments made to store the small HOT WHEELS cars. I put my embroidery threads in the boxes according to colors. I can immediately see the colors I need. These boxes have a handle on them so they are easy to grab to move to take.
When starting an embroidery project I get out a egg carton. I have several that are clear plactic. I put the treads in according to stitch use. When I use the same color several times I just put a slip of paper in the appropriate compartment telling me the preivous use number. If I am doing my work away from home I have a perfect container to carry the thread home in and still have the treads stored according to use. Since I don’t have a designated sewing room the egg carton is a perfect place for me to keep the threads and put them away until the next time I come back to complete the project.