If Im playing outside and its cold (my lower limit is 50 degrees), Tourna Mega-Tac is my go to. I did this last week and just put one over another overgrip.
For general use with just a little tack, Ive enjoyed Technifibre Pro Contact, Yonex Super Grap, Solinco Wonder Grip and Gamma Supreme. (White preferred)
My hands dont sweat a lot, but if Im playing in 90+ degree heat, I like Völkl V-Dry and the Yonex Dry grap.
I picked up a pack of the black Yonex Dry grap at the end of the summer, and it was completely different than the green. The green had this supple, microsuede-like feel and the black is like dry sandpaper. Has anyone else tried both and got that impression? Sometimes I think the quality can vary with the same overgrips. Like I will use one and think to myself "wow, this one is lasting a long time and maintaining it's tack." Then I'll try another of the same type and think it isnt nearly as good as the last one. Manufacturing variances? Degradation from sitting for a while? Who knows.