www.britannica.com has under Monotheism (Theology):
*Chinese Lord-on-High - (1600–1046 bce)*The religion of the ancient Chinese Shang dynasty (1600–1046 bce) featured belief in the Lord-on-High (Shangdi), who is comparable in many ways to the high god of other religions.
*Zoroastrianism - Supreme God Ahura Mazdā (7th–6th century bce)*Some religions are in the main dualistic; they view the universe as comprising two basic and usually opposed principles, such as good and evil or spirit and matter. Insofar as the conception of a god and an antigod rather than that of two gods is encountered, this kind of religion can be considered another variation of monotheism… The most important instance of dualism within a religion is the Persian religion Zoroastrianism as founded by Zoroaster (7th–6th century bce), in which Ormazd (Ahura Mazdā, the “Wise Lord,” or the good, supreme god) and Ahriman (Angra Manyu, the destructive spirit) are each other’s opposite and implacable enemy; at the end of time, Ormazd will defeat Ahriman.
Also Deuteronomy 6:4 is purely monotheistic: Hear, O Israel, the Lord our God is one Lord.
Yet, the people fell into idol worship at times after that.
Judiasim - Yahweh (6th century bce)“There may be some reason to speak of the conception of God found in the Hebrew Scriptures as monolatry rather than as monotheism, because the existence of other gods is seldom explicitly denied and many times even acknowledged … In later times—beginning in the 6th century bce and continuing into the early centuries of the Common Era—Jewish monotheism developed in the same direction as did Christianity …”
britannica.com/topic/monotheism