Documentation Theme for Gatsby from Adobe
Theme created by Adobe developers. They use it for product, platform pages and documentation. And of course the most useful this theme would be for documentation site creators.
UI developed using spectrum-css library of their own. It also leverages preact library for performance reasons.
This theme is VERY feature-rich, and have pretty decent documentation.
Google Docs support
OpenAPI specs rendering
Adobe I/O CLI(optional)
Modular Content System
Number of Block components