Some "Known" early sources of Abraham traditions
(see also shorter sections of works on other subjects):

• Genesis
• Genesis apocryphon (and a couple of references in CD)
• Jubilees [12 in Ur, Abr destroys idols; in Haran, he studies stars, confesses God]
  
• Artapanos (Eusebius Prep 9.17.2-9)
  
• ps-Eupolemos (Eusebius Prep 9.18.1)
• unattributed fragment (Eusebius Prep 9.18.2)
  
• Philo (passim)
  
• Josephus, Antiquities
  
• LAB (briefly)
  
• Testament of Abraham (in two recensions)
• Apocalypse of Abraham (Slavonic)
• "Abraham" (Nicephorus list, 300 lines, or 1300 or 3300)
  
• a Sethian Apocalypse  (according to Epiphanius)
• Books of the three Patriarchs (according to Apostolic Constitutions)
• Origen quote (on Luke, Hom. 35). "We read -- at least if any one likes to accept a writing of the kind -- of the angels of righteousness and of iniquity disputing over the salvation or perdition of Abraham, each band wishing to claim him for its own company."
• materials in Jeffrey Siker, "Abraham in Graeco-Roman Paganism," JSJ 18 (1987) 188-208
  
• Rabbinic traditions (reported in Ginzberg, Legends of the Jews & Kugel, Traditions of the Bible)
• Quran and Islamic traditions ( Reuven Firestone, Journeys in Holy Lands: The Evolution of the Abraham-Ishmael Legends in Islamic Exegesis [State University of New York Press, 1990]) -- "According to the legends, Abraham discovers the religious truth of monotheism through a series of personal experiences
  and trials in the land of the East, culminating in his opposition to the spurious religion of the tyrant Nimrod. Nimrod counters by having him thrown into a fiery furnace, which is miraculously cooled by a miracle of God. Abraham finally leaves his own land and people in order to worship the one God and practice his religion as he knows he must. His emigration is mentioned or assumed in the Qur'ān in "Sūras" 19:48-9, 21:71, 29:26, and 37:99, but a full picture can be found only in the exegetical literature."