Gold Frogs are Baby Frogs that can be collected just like the others, but are not mandatory for a level to be completed. They do not make Frogger's time reset or have him return to his start position like the other baby frogs. When collected, their jingle is a string-like harp chord.
These are the levels where a golden frog can be found.
Lily Pad Zone-Spinning Lillies
Mechanical Zone-Scorching Switches
Cactus Zone-Crumbled Point