CKEditor - Real-time collaborative future-ready rich text editor
Monokai JSON+ - Sublime Monokai Theme for JSON.
TinyMCE - TinyMCE is a content editor that functions as a plug-in for Wordpress websites.
Power JSON Editor - Power JSON Editor is a JSON editor for developers with Visual Tree View and multiple plugins like Array Table Editor and jq Processor, also with format converter plugins, it is easy to convert files between JSON, PLIST, YAML and TOML.
Quill - Powerful, API-driven rich text editor
FundaMine - Get Medium style annotations on your site