I believe it might be a Tree Frog. Tree Frogs usually range from Green to Brown and to even Grey. Another characteristic of a Tree Frog is that the species has long toes and the feet are indeed yellow.
yellow and grey = black :)
dark grey or black.
dark grey or black.
red,black,,brown,grey,yellow
red,black,,brown,grey,yellow
black grey white yellow
black grey white yellow
private collection
black, white, grey and yellow
black colour
dark yellow with black spots
Blue white grey yellow black