I have read that in his last sermon, Muhammad (PBUH) mentioned the Quran and Sunnah.
I leave behind me two things, the Qur'an and my example, the Sunnah and if you follow these you will never go astray. (alim.org)
But some people dispute it and say Sahih Sitta books contain hadiths about the Quran and his Family.
ألا أيها الناس فإنما أنا بشر يوشك أن يأتي رسول ربي فأجيب، وأنا تارك فيكم ثقلين: أولهما كتاب الله فيه الهدى والنور فخذوا بكتاب الله، واستمسكوا به فحث على كتاب الله ورغب فيه، ثم قال: وأهل بيتي أذكركم الله في أهل بيتي، أذكركم الله في أهل بيتي، أذكركم الله في أهل بيتي
"O people, I am only human, and soon the messenger of my Lord will come to me and I will respond. I am leaving among you two weighty things, the first of which is the Book of Allah in which is guidance and light. Follow the Book of Allah and hold fast to it." And he encouraged us to adhere to the Book of Allah, then he said: "And the people of my household, I remind you of Allah with regard to the people of my household, I remind you of Allah with regard to the people of my household, I remind you of Allah with regard to the people of my household."
— Sahih Muslim, كتاب فضائل الصحابة - باب من فضائل علي بن أبي طالب رضي الله عنه - (sunnah.com)
Can we find the hadith which supports the view point of Quran and Sunnah?