Non-denominational Muslim
A non-denominational Muslim is a Muslim who does not belong to, does not self-identify with, or cannot be readily classified under one of the identifiable Islamic schools and branches. Such Muslims do not think of themselves as belonging to a denomination but rather as "just Muslims" or "non-denominational Muslims." Muslims who do not adhere to a sect are also known as non-sectarian Muslims.
Source: Wikipedia — Non-denominational Muslim (CC BY-SA 4.0)