It’s always interesting to bump into previously unknown services and sites, but these lists tend to get outdated over time. The most recent commit on this one was in April 2020 (a whole year and a half ago), and it shows.

Going through the first few items, I see volatile.wtf showing an under construction page, and Formspree requires registration.

I’m getting to know of new/unknown (to me) sites, but I’ll ignore the “no registrations” qualifier in the title.