Neptune's 7th moon Triton is in a retrograde orbit

and although it isn't a moon Venus is in a retrograde orbit

When a moon's orbit is backwards, it is referred to as a retrograde orbit.

retrograde

None of the eight planets in the solar system has a retrograde orbit. However, two, Venus and Uranus, have retrograde rotation around their axes. As to whether any exoplanet has a retrograde orbit or not, that is unknown since there is little or no knowledge of their rotation.

Neptune's moon, Triton