I got tired of trying to moving around my breadboard and Uno projects with 2 hands. So i saw some where someone made a caddy for the two. I added another pocket for a small board. The small board is usually a board I use with my bread boarding of a project that it contains switches and or lights. This is my angled version but I also made a version where the Uno and the accessory board is flat.

I do plan on adding a battery mounting system in the cavity that is in the back of this model. That way I can carry it around and keep it powered up for testing various processes that need to be done while not tethered to a PC or other device.