[naraht]

I"m presuming that you aren't considering any groups with Christian in their full name. Other than that, the only ones that I'm familiar with that require belief are Kappa Sigma (which has already been mentioned in the thread) and Omega Psi Phi (which I'm guessing isn't a group in the Formal Rush, being NPHC).

I'd like to add the suggestion to check with National Fraternity websites. My service fraternity, Alpha Phi Omega, for example includes in the National Pledging Standards "Pledges should be made aware that the Official Fraternity Initiation Ritual contains references to God and a dedication invoking the name of “Our Common God”.", however religious belief is not required...