What is the ruling on one who denied an attribute of Allah Almighty, but does not remember what it was, and what should they do?

Sincere repentance and seeking forgiveness are sufficient to atone for sins, for Allah forgives all sins for whoever repents, even sins that the servant is unaware of. Thus, comprehensive prophetic supplications have been reported for seeking forgiveness from all sins, such as: "O Allah, I seek refuge in You from associating partners with You knowingly, and I seek Your forgiveness for what I do not know."