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 Wisget is availble for free but it can also be purchased. There is no a difference between the paid and free versions. Please support the creator by purchasing the paid version if you can.
Review and Tutorial by CGDive
Get it on GitHub
Get it on Gumroad (pay-what-you-want)
Get it on Blender Market ($5/$25 Donation)
Tutorial by Blender Defender
Addon History
Bone Widget was originally developed by ChristopheSeux. Later it was forked and developed further by Wayne Dixon (waylow), adhihargo, and Blender Defender. However, the only actively devloped version seems to be that by Blender Defender. You will find links to the other repos below so do check if they got updated as well!