Study the following sentence

She is one of the few women writers who have won the Nobel Prize for Literature.

Here the verb have is plural because its subject who has a plural reference (the few women). However, the sentence is also saying She has won the Nobel Prize and in an informal style many people would therefore say ‘She is one of the few women writers who has won the Nobel Prize for Literature’. This is not strictly correct because the verb in the relative clause should agree with the subject of the relative clause and not with the subject of the main clause. However, structures of this kind are very common in informal English.

He is one of the few players who have been selected for the tournament. (Formal)
He is one of the few players who has been selected for the tournament. (Informal)

She is one of the students that were absent today. (Formal)
She is one of the students that was absent today. (Informal)

When the singular subject is modified by a following plural expression, people sometimes use a plural verb. However, this isn’t considered correct.

Nobody except his parents like him. (More correct: Nobody except his parents likes him.)