UrhoSharp

With a small footprint of ~10MB per platform, it can be easily embedded as a subview in UI frameworks like UIView or WPF Panel, making it ideal for integrating 3D into existing apps.

Runs on Windows, macOS, iOS, Android, UWP, and even AR platforms like HoloLens, ARKit, and ARCore, allowing for maximum code reuse across devices.

Features physically based rendering, skeletal animation, and inverse kinematics, enabling high-quality visuals comparable to more heavyweight engines.

Both the C# bindings and underlying Urho3D engine are licensed under MIT, providing freedom for commercial use and modification without legal hurdles.