I use a few tools together with my printer all the time. These are Allen hex keys, electronic calipers and a USB adapter for microSD cards. I decided to make holders for the tools that are printable in PLA and snaps in place without the need for screws. This particular thing is a holder for a set of Allen hex keys. I added a retaining bolt hole to the holder. This was probably overkill. It seems to stay in place just fine without any bolt. I made another variant of the holder where the clip is vertical rather than horizontal. That version can be found here: http://www.thingiverse.com/thing:518290