I've been interested in making some 3D web games. After a review of some of the available engines I stumbled across Babylon. This seems like a bit of a hidden gem and it's used by a few real-world projects like Xbox Design Lab (https://xboxdesignlab.xbox.com).

It's been shared here a few times but I thought I'd surface it again in case anyone else is looking for a small, fast, web-based game engine and this has flown under their radar.