Tangram - an open-source map renderer.

Tangram is an open-source map renderer designed to animated shaders, 3D buildings, and dynamic filtering can be combined to produce effects normally seen only in science fiction.
The Tangram Play is an interactive text editor for creating maps using Mapzen’s Tangram rendering engine.
 Also, you can write and edit map styles and preview the changes live in the web browser.

Another online editor for three.js projects.

The framework named three.js let you to create cameras, objects, lights, materials and more, and you have a choice of renderer.
The default editor of this framework can be found here.
Today I will introduce you a new editor that allows you to edit html online.
From my point of view, this new editor is a more versatile way of creating content with this framework.

You can load this new editor here, here is a screenshot: