I couldn't find this question here, but I would like to be able to search all sites in the SE network except some sites. In my case, I want to remove the thousands of results from SO on a popular project for devs so I can see the handful of results on other sites from admins and users.
The current form only allows all sites or listed sites.
The answer linked does not tell me how to use the information in the answer. It is a poor answer for an average user.
As @Laurel describes in the comment below, the answer at Exclude specific site from search result no longer works.