Interesting...it looks like https://pixelfed.sdf.org/ exists, but there's no way (that I can find, at least) to join it.
Where most instances have a "sign up" link is just blank space here.
It's kind of frustrating.
Nope, you have to ask the SDF admins.
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko