The Abrahamic religions are Judaism, Christianity, and Islam, so-called because they are all descendants of the religious tradition of Abraham, the biblical patriarch. The term desert monotheism offers an alternative descriptive categorisation. The standard Islamic name for the other two monotheistic religions is People of the Book.
There are six notable figures in the Bible prior to Abraham: Adam and Eve, their sons Cain and Abel, Enoch who was "taken by God" and Noah, his great-grandson, who saved his own family and all animal life in Noah's Ark. These people did not however leave any recorded moral code behind - they serve simply as good and bad examples of behaviour but there is no specific indication of how one interprets their actions in any religion.
Islam considers Adam and Noah to be prophets, and also considers the wisest lawgivers of other nations (Confucius, Hiawatha) to be prophets as long as they claimed no divinity on their own behalf. Judaism historically accepted that each people had its own god, of which theirs was simply the most powerful. Many strains of Christianity up to the 20th century considered some or all other faiths to simply be idolators, heathens, heretics, paganss, blasphemers, or merely misguided.
So rather than being the sole "founding figure", it is more correct to say that Abraham is the first figure in Genesis that (a) is clearly not of direct divine origin such as Adam and Eve are claimed to be (b) the three major desert monotheist faiths accept as playing some major role in the founding of their common civilization (c) is not claimed as the male genetic forebear of all humans on the Earth (as Noah is, in more literal interpretations - Cain by contrast married a woman from the "Land of Nod" who was unrelated to him or Adam) (d) is quite well-documented.
In the Book of Genesis, Abraham is specifically instructed to leave the city of Ur so that God will "make of you a great nation", and his travails thereby are well documented. Burton Visotzky, an ethicist, wrote Genesis of Ethics to explore the detailed implications of these adventures for a modern ethics.
According to the Bible, the patriarch Abraham (or Ibrahim, the Arabic version) had two sons: one (Ishmael) by his wife's servant Hagar, and one (Isaac) by his wife Sarah. According to this account, Jews are descended from Isaac's son Jacob, also called Israel. Biblical Judaism is based on the covenant between God and the "children of Israel" (descendants of Israel's twelve sons) at Sinai.
Christianity recognizes Jesus, who had at least a Jewish mother, as its messiah, as the son of God, and as being part of the Godhead himself. Islam recognizes Jesus and the Jewish prophets after Abraham (such as Moses) as being divinely inspired (though not divinely born), and in a crucial distinction recognizes Muhammad (the religion's founder) as a prophet - the last.
Although the Baha'i Faith is not traditionally included among the Abrahamic faiths, it recognizes the same prophets, plus Bahá'u'llá'h. Rastafarianism similarly recognizes Biblical authority and believes itself to be a descendant of the religion of Abraham. Most Bibilical prophets are recognized, along with Emperor Haile Selassie and Marcus Garvey.
There are other religions that recognize, to a greater or lesser degree, the prophets of the Bible, the various Voodoo faiths (a syncretic blend of Christianity and African pagan religions), and Unitarian Universalism.
See also: Monotheism, Judaism, Christianity, Islam , Judeo-Christian tradition, Christo-Islamic tradition , Religions of the world, vedic religions
