JOHN THE BAPTIST AND THE MANDAEANS
One religion exists to this day that reveres John as their main prophet:
The Mandaeans were originally native speakers of Mandaic, a Semitic language that evolved from Eastern Middle Aramaic, before switching to colloquial Iraqi Arabic and Modern Persian. Mandaic is mainly preserved as a liturgical language. During the century's first decade the indigenous Mandaic community of Iraq, which used to number 60-70,000 persons, collapsed in the aftermath of the Iraq War of 2003; most of the community relocated to nearby Iran, Syria and Jordan ... proclaiming the chief Mandaean prophet to be John the Baptist, [Wikipedia]