Where in the menu system is the link to this blacklist?
As referenced in the codex https://codex.wordpress.org/Multisite_Network_Administration
Also note that the blog prefix is not used for static pages which will be accessible directly under the base address, e.g. domain.com/PAGENAME. If you try to create a static page in the first site with the name of another existing site on the network, the page's permalink will get a suffix (e.g. domain.com/PAGENAME-2). If you create a new site with the slug of an existing static page, the static page will not be reachable anymore. To prevent this, you can add the names of your static pages to the blacklist so that no site with that name can be created.
After a few different searches I cannot find another reference to this static pages blacklist. I want to add a few pages like "contact,about,ect...". I have my wordpress setup and using multi-site.