Today i found on Reddit that, the mirror of userscript.org is now called http://webextender.net. I don’t know how reliable or functional it is at this moment, but i was looking for the search option, and found it there.
Soon after Userscripts.org was taken down, it was still accessible at http://userscripts.org:8080
Till now the site is accessible at http://userscripts-mirror.org/ with limited functionality (search disabled and stuff).
So, here are some of the sites that can be used to get userscripts for Greasemonkey (Firefox) or Tampermonkey (Chrome).
Read more about the sources here.