Not sure but are you wanting to copy constraints from one bone to selected bones? If so blender already does that. Select the bones you want to copy constraints to. Then Shift+select the bone with the constraints so that it’s the active bone. Then click Pose menu->Constraints->Copy constraints to selected bones. Note: It does remove any constraint already on the selected bones. if you want to select by pattern then that’s under select menu.
***Edit**
You need to be in pose mode. If you want to do it across multiple armatures then you need to select all armatures in object mode before switching to pose mode.
