Abu Ubaydah narrates that the voluntary prayer which Sayyiduna Abdullah (may Allah be pleased with him) never abandoned was as follows: four rak'ahs before Zuhr, two after it, two after Maghrib, two after Isha, and two rak'ahs before Subh (the dawn prayer).
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9410