I am largely including this in my list because it is listed in the Book of Concord as a heresy. What say you as to its status as a heresy?
Mohammedanism: Mohammedanism is listed by Lutherans as a heresy in the 1530 Augsburg Confession. While Islam is not usually considered a Christian heresy, there is some significant evidence suggesting a link to Arianism, and that Mohammed likely based what he used in the Qu’ran from the Bible out of an Arian Bible. Clearly, the Islamic view of Jesus is in line with Arianism by denying His deity. Since they deny the Trinity, this is also an antitrinitarian heresy.