I think I have tried them all.
Tournagrip is the best in humid environments due to the absorbency factor. It is more cloth-like than the tacky white overgrips like Wilson Pro, Gamma Supreme or Yonex Supergrap. The pros get them for free and change them every changeover. They are great at soaking up the sweat.
I recently tried the white Kneissel Tournastar overgrips and they were sort of a hybrid in between cloth Tournagrips and the white plastic tacky ones. I think I got them on the bay. They were actually pretty good so I might get some more of those.
I have used some other Alpha overgrips that became slippery when wet. Not such a good thing for an overgrip.