Sunan Abi Dawud Book 5, Hadith 4
The Prophet (ﷺ) never omitted four rak'ahs before the noon prayer, and two rak'ahs before the dawn prayer.
The Messenger of Allah (ﷺ) would pray two rak'ahs before and two after the noon prayer, two after the sunset prayer in his house, and two after the night prayer. He would not pray after the Friday prayer till he departed. He would then pray two rak'ahs.
The Messenger of Allah (ﷺ) was more particular about observing the supererogatory rak'ahs before the dawn prayer than about observing any of the other supererogatory prayers.