I’ve worked with hundreds of different horse and buggy Mennonite and Amish, Messianic Jews, Charismatic, New Age, Interfaith, Jewish, Buddhist, Hindu, and yes, a few Islamic groups, and a few cults. This in addition to all the mainstream denominations. My specialty for many years was clergy & church related income tax laws. Traveled the USA teaching workshops and taught it at many universities and seminaries. I did several hundred clergy tax returns per year in my office and did training programs for church treasurers. Thus my exposure was quite diverse.
Now retired, but still stay somewhat current on the laws.
One of the most unusual was a group where women who were having their periods were considered unclean and were required to sit in the back, away from the congregation by themselves.
One example is the limitations placed upon education by the Amish & Old Order Mennonites. Rules for dating, dress requirements, subservience.
I hosted a presentation/workshop a few years ago by Adel Wilcox who wrote a book on suppression and abuse of women who were told by their pastoral counselor that it was their own fault as they were not subservient enough. She ran a retreat center in PA dealing with women who are mistreated by religious doctrines. She is a Methodist Minister.
Strict rules about dress and dating need not constitute mistreatment.
For example, the Duggars, presumably Southern Baptist, have strict rules about dress and dating and the wat they run their family isn't mistreatment.