what frats do sororities and girls like the best?

Depends on the girl. Different people like different things.

In general the order of the rankings that "desirable girls" date frat bros is the same as the "consensus list" of frats. Sig Ep and Sigma Chi probably do the best overall in that department if that's the only factor you care about.

A couple of interesting aberrations. ZBT and Sammy tend to pull waaayyyy better than their "rank" would indicate. For a "top 3" SAE tends to pretty badly underperform with "smokeshows." The reasons for those are many of the ZBT kids are loaded, Sammy is its own thing and SAE guys are less shallow.