I have the most confidence with a black frog in cloudy/overcast or low visibility water and a white belly frog in blue bird sky's with water thats in general more clear. Can't beat beat a black frog though keep it simple, if the frog bite is on its on!
Agree with the above for regular hollow body frogs. For standard conditions (a few clouds, but mostly sunny) I also like the natural light green almost cream colored, maybe with a little chartreuse toward the head and black dots on the belly.
For popping and buzz frogs, it's more of a reaction bite and I feel color matters less, but I try to stick with black or white as the predominant belly color on those also.
With the really muddy water we've had recently, I've had more success with reaction type frogs with a little louder belly color scheme--leopard and greenish orangish/reddish bellies.