Unity

• De-Panther's WebXR Export (https://github.com/De-Panther/unity-webxr-export)
• Needle Engine (https://needle.tools/)

Godot

• dsnopek's Godot + WebXR Tutorial (https://www.snopekgames.com/tutorial/2023/how-make-vr-game-webxr-godot-4)

Engines that can build for WebXR

• Wonderland Engine (https://wonderlandengine.com/)
• Rogue Engine (https://rogueengine.io/)
• Playcanvas (https://playcanvas.com/)

Web-based Libraries and Frameworks

• A-Frame (https://aframe.io/)
• babylon.js (https://www.babylonjs.com/)
• three.js (https://threejs.org/)
• React XR (https://github.com/pmndrs/react-xr)