/ Choose Proto.io - Prototyping for all if
Its stated focus matches what you need: Build interactive web, iOS, Android, and other low or high-fidelity prototypes right into your web browser. Drag and drop ready-to-use, easily customizable templates, UI components, icons, and more, to prototype in minutes! No coding skills required.
/ Choose Spline - 3D Design tool in the browser with real-time collaboration if
Its stated focus is closer to your workflow: Spline is a free 3D design software with real-time collaboration to create web interactive experiences in the browser. Easy 3d modeling, animation, textures, and more.