I've seen some very clever ways to store bobbins but none were a perfect match for the number of bobbins I have (not that many) or the space I have to store them. So I came up with a solution that works for me. Now my bobbins don't roll around, the thread doesn't unspool and at a glance I can see what colours of threads I have on bobbins.
I use drinking straws to restrain my sewing machine bobbins. I cut a drinking straw in half, place the two pieces together and slide the bobbins onto them.
The straws push against each other and that keeps the bobbins from sliding off the straws.
The thread ends can be wound between the bobbins or tucked between the two straws.