Teletype for Atom : Teletype for Atom lets developers share their workspace with team members and collaborate on code in real time.
Bottery : Bottery is a syntax, editor, and simulator for prototyping generative contextual conversations modeled as finite state machines.
Slate : Slate is a completely customizable framework for building rich text editors.
Slate lets you build rich, intuitive editors like those in Medium, Dropbo...
TinaCMS : Tina is an open-source site editing toolkit for React-based sites like Next.js & Gatsby to build content management directly into your website.
MobWrite converts forms and web applications into collaborative environments. Create a simple single-user system, add one line of JavaScript, and instantly get a collaborative system.