Who are the monotheists among the People of the Book? Are they found today, and if so, where, and what do they believe in?

The monotheists whose monotheism benefits them in the sight of Allah are those who believe in Allah as the sole Creator and God, without any partners, and affirm everything brought by the messengers from Allah without differentiation. There are no monotheists in this sense in this era except within Islam. As for Judaism and Christianity, there are no monotheists in this sense within them; rather, they are polytheists and deniers of what Muhammad (peace and blessings be upon him) brought. Every Jew and Christian who dies upon that is a disbeliever, abiding eternally in the Fire.