Bone Widget addon
The Bone Widget addon allows you to apply a number of common bone shapes to any bone with a single click. You can even create your own custom shapes and save them for later use.
Bone Widget is availble for free.
Review and Tutorial by CGDive
Get it on GitHub
Note: there are two version of the addon that should be up-to-date and work similarly. As of the writing of this article, I recommend the version by “waylow” because it is actively developed and has the most features. But I encourage you to test both:
https://github.com/waylow/boneWidget/
https://github.com/BlenderDefender/BoneWidget
Addon History
Bone Widget was originally developed by ChristopheSeux. Later it was forked and developed further by Wayne Dixon (waylow), adhihargo, and Blender Defender.
You will find the different repose below.