Ibn Hazm is one of the senior scholars and one of those who respected the Sunnah and its people, and were keen to learn it and follow it. Ibn Hazm differed from Ahl as-Sunnah with regard to many important issues having to do with both fundamental and minor matters, which made many of the scholars criticize him and highlight his mistakes in beliefs.

The Khawarij (Kharijites) are followers of whims and desires and innovation who have deviated from the path of Ahl as-Sunnah wa’l-Jama`ah but we do not describe them as disbelievers because of their innovations.

The Maturidis are a philosophical group based on innovation (bid‘ah); they are named after Abu Mansur al-Maturidi. Please see the detailed answer for differences between Maturidis and Ahl as-Sunnah.