Quss ibn Sa'ida of Banu Iyad was one of the hunafa', an old man of 80-90 by the time the Prophet ﷺ, then a young man in his twenties, saw him. He would come to Makkah for the hajj and preach against idolatry, and was renowned as one of the most eloquent poets of his time, his language said to resemble that of the Qur'an itself.
His preaching, along with that of the other hunafa', shows that some knowledge of tawhid and a rejection of idolatry survived among individual Arabs even at the height of Jahiliyyah.
Other events recorded around the same time. Their order within the year is not established; use the storyline above for the sequence.
يا أيها الناس، اسمعوا وعوا، وإذا سمعتم شيئا فانتفعوا، إنه من عاش مات، ومن مات فات، وكل ما هو آت آت
O people! Listen to me and understand! And when you hear, then benefit! Because whoever lives, of a surety will die! And whoever dies, has finished! And everything that Allah has decreed, will indeed come about!
يا معشر إياد، أين ثمود وعاد، وأين الآباء والأجداد، أين المعروف الذي لم يشكر، والظلم الذي لم ينكر، أقسم قس بالله إن لله لدينا أرضى من دينكم هذا
O people of Iyad! Where is Thamud, and where is Ad? Where are your fathers, and where are your grandfathers? And who will reward the one who does good but is never rewarded? And who will punish the one who does injustice but is never punished? I swear by Allah that there must be a religion better than the religion you are upon!