TL;DR of the post, generated automatically.

OP shares three free Blender Python scripts for animation work.

• Scripts: Reflective IK (auto-rig), arc path loose bone, proportional posing.
• Versions: Written for Blender 5.2 LTS and 5.3, but OP says each needs polish.
• Note: Reflective IK works best alongside the arc script for FK behavior.