There may be, you can search here:
Resources
However, as a concept, password rules are fairly useless. They only really serve to make the process of choosing a password more cumbersome than it needs to be and really only leads to users being predictable such as choosing common patterns or replacing common letters with common symbols and so on.
This is why XF 2.1 has a password strength meter. It gives users a good analysis of their password choice and helps educate them into choosing a better password.