Amulets found in Syria in 1933 have on them a word which could be Lilith. Originally dated to the 7th century BCE, other scholars believe they are from a much later Jewish community.
Sumer and Babylonia
Evidence for a spirit called Lilith -- or something like that -- being quite ancient is found in a story about Gilgamesh, an addition to the Epic of Gilgamesh. Gilgamesh, the hero, confronts three spirits in a tree, spirits the goddess Inanna is afraid to confront. He kills a snake and scares away both Lilith and a bird. The identification of Lilith with the serpent in the Garden of Eden may be rooted in this tradition. These references are questioned by many scholars and there is not consensus on these being Lilith references.
In Akkadian, the word for Lilith, Lilitu, has a male counterpart, Lilu. Lilu attacks men, and Lilitu has a woman's face, wings and long hair. These names appear in incantations from Babylonia, about 600 BCE.
A terracotta plaque called the Burney Relief, likely from about 1800 - 1750 BCE, was identified as showing Lilitu. However, later scholars have suggested that the figure is Inanna (Ishtar) or Ereshkigal instead, and the identification is still controversial. Some of the symbolism -- bird feet and owls -- are more indicative of Lilitu; some more of the goddess of love and war (lions).
In Isaiah 34:14, Lilith is named, being among the spirits or unclean animals connected with the day of judgment. In the version of Isaiah found in the Dead Sea Scrolls, the plural is used, liliyyot instead of lilit.
Greek and Roman Mythology
Later Latin translations of that verse in Isaiah used the word Lamia or Lamya. This has been connected with a Greek tradition of a Lamia who was a demon who steals children. Lamia was considered the mother of Scylla.
Biblical Lilith in Genesis
Although the name "Lilith" does not appear in Genesis, there is a tradition from medieval times of reading certain passages as referring to Lilith. These explain seeming contradictions in the text.
In Genesis 1:26-29, male and female are both created. Yet in Genesis 1:26-29, Eve is formed after Adam, shaped from one of his ribs.
Genesis 1:26-29 and Genesis 5:1-2 can be read as the female and male being created at the same time, but only the male being created in the image of God.
Genesis 1:26-29 gives permission to Adam and the first woman to eat the fruit of all the trees in the Garden, and then Genesis 2:15-25 prohibits eating of the tree of knowledge.
The Testament of Solomon
A Greek Christian text of the 3rd century CE mentions a female demon of many names who threatens newborns.
Dead Sea Scrolls
Lilith is mentioned in Songs of the Sage as one of a list of monsters (the singular is used rather than the plural). The texts in the Qumran collection date from about 400 BCE to just after 300 CE.
The Babylonian Talmud
Lilith is mentioned by name in several passages in the Talmud (about 400 CE). The passages seem to assume that the hearer/reader will know about Lilith, which speaks to there being an oral tradition about Lilith by this time. She is mentioned as a demon who seizes those who sleep alone. She is mentioned as having long hair (in a context which implies she is a demon). A son of Lilith is mentioned. Adam, described as spending 130 years separated from Eve and fasting in regret for bringing death to the world, is said to have conceived male and female evil spirits during wet dreams by "a Lilith." Another passage describes an aborted child who had wings and thus was like Lilith.
In Babylonian territory in the time of the Sassanid Persian Empire (3rd to 7th century), bowls with inscribed incantations mention Lilith (male and female versions). It is not known if these are Jewish or non-Jewish artifacts.