r.average
r.average - Finds the average of values in a cover raster layer  within areas assigned the same category value in a user-specified base layer.
Raster (r.*)
ParameterRaster|base|Base raster layer|False
ParameterRaster|cover|Cover raster layer|False
ParameterBoolean|-c|Cover values extracted from the category labels of the cover map|False
OutputRaster|output|Average values