MnO42- exhibits d-d transition and paramagnetism as well.
CrO42- => Cr6+= [Ar] => Unpaired electrons= 0, Diamagnetic
Cr2O72- => Cr6+= [Ar] => Unpaired electrons= 0, Diamagnetic
MnO4- => Mn7+= [Ar] => Unpaired electrons= 0, Diamagnetic
MnO42- => Mn6+= [Ar]3d1 => Unpaired electrons= 1, Paramagnetic