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.
Strut : An HTML5 Presentation Editor. A GUI / Authoring Tool for ImpressJS and Bespoke.js
Source at https://github.com/tantaman/Strut
Slate : Slate is a completely customizable framework for building rich text editors.
Slate lets you build rich, intuitive editors like those in Medium, Dropbo...
NicEdit : WYSIWYG Content Editor, Inline Rich Text Application
Expo : Expo is a framework and a platform for universal React applications. It is a set of tools and services built around React Native and native platforms ...
A React-powered node editor and runtime engine. Build apps that are resilient to changing requirements by modeling your business logic as a JSON graph. Flume provides a sleek UI for creating and editing these graphs.