Here is a list of retracted Covid-19 papers, as collated by Retraction Watch:
https://retractionwatch.com/retracted-coronavirus-covid-19-p...
https://retractionwatch.com/retracted-coronavirus-covid-19-p...
“Worst paper of 2020?” https://scienceintegritydigest.com/2020/07/23/worst-paper-of...