bones – Oded Maoz Erell's CG Log

Blender 2.8 – Select bones in Weight Paint mode

Software:
Blender 2.8

To select bones while in Weight Paint mode in Blender 2.8:

Select the Armature
Shift select the skinned mesh
Switch mode to Weight Paint
Shift-Click bones to select them
* Shift double click to select bones hidden under the mesh

Software:
Blender 2.83

To copy bone constraints from one bone to other bones:

In Blender Preferences > Add-ons:
Find the Interface: Copy Attributes Menu add-on, and enable it.
In Armature Pose Mode,
Select one or more bones, and select last the bone that has the constraints you want to copy.
Press Ctrl + C to open the Copy Attributes menu, and select Copy Bone Constraints.

Related post:
Quickly setup bone constraints

Software:
Blender 2.8

To mirror a skeleton (Armature) in Blender:

Create bones for one side of the rig and name them with “.L” for Left or “.R” for right.
Select all the bones on that side.
In Armature Edit Mode choose:
Armature > Symmetrize

Blender will create mirrored copies of all the bones with respect to the Armature origin and flip their names to names ending with the opposite side.