Like many people say Google is your friend, and with reason.
This little trick will tell you how to "Find trackers opened for Signup" using Google.
It's very very simple, just go to google and in the text field paste this:
Basically Google will try to find "inurl" a page named "signup.php" which includes the word "Torrents" on the page.Code:torrents inurl:signup.php
So, you can try to change the name of the page to find and maybe you'll find something else.
Hope you like the little tipCode:torrents inurl:account-signup.php