Oh you know, the Arians, Nestorians, Marcionites, Paulicans and various other gnostic heretics.
The YOPIOS crowd seems to operate under the assumption that every sect that was ever declared heretical by the Catholic Church was really just a group of oppressed Protestants who just wanted to be left alone so they could practice YOPIOS. They seem incapable of understanding that these groups were actually misguided heretics and their heresy was almost always based in their denial of the Divinity of Jesus Christ or the Holy Trinity.
“The YOPIOS crowd seems to operate under the assumption that every sect that was ever declared heretical by the Catholic Church was really just a group of oppressed Protestants...”
What’s laughable is that every point in Christianity from Christ’s nature and so forth right on to the Trinity, they owe to the Catholic Church, to the Fathers and to the Counsils.
The “ancient Baptists” or “Roman Unitarians” didn’t exist.
A lot of their current misinformation is due to the re-writing of the history of Constantine’s reign to infer that he suppressed all the Christians who went underground at some point and resurfaced in the 17th and 18th century.