You can purchase the latest version of the OutlineSystem in the Unity Asset Store. When you have purchased it, you will be able to download it in the Unity Asset Store
For simplicity, the license is the same one as the Unity Asset Store uses. Check the asset store for the exact specifications. It does allow for commercial usage.
The OutlineSystem costs $90 (+VAT if applicable).
CosterGraphics Outline System
CosterGraphics OutlineSystem for the Unity Universal Render Pipeline
A highly versatile and easy to modify system for rendering professional Screen-Space Edge-Detection based selection Silhouette & Contour Outlines and Overlays around any 3D model in the Unity game engine.
Fully utilizes the Unity Render Graph API and Shader Graph shaders, to efficiently render sharp and technical, or highly stylized NPR outlines, onto selected GameObjects only or onto the entire scene.
Also contains many other full-screen edge detection and overlay effects for full-screen NPR styles and sci-fi effects.
Built for the Universal Render Pipeline.
CosterGraphics 