Hazrat Musleh-e-Maud (ra) states that the names of prominent huffaz [those who have memorised the entire Quran] from the Ansar were Ubadah bin Samit (ra), Muaz, Mujama bin Harithah (ra), Fuzalah bin Ubaid (ra), Maslamah bin Mukhallad (ra), Abu Darda (ra), Abu Zaid (ra), Zaid bin Thabit (ra), Ubayy (ra) bin Kaab, Saad bin Ubadah (ra) and Umm Waraqah (ra).
(Dibachah Tafsir al-Quran, Anwar al-Ulum, Vol. 20, p. 430)