The PlayStation Plus games for September 2019 are now live, and available to download from the PlayStation Store. This months line-up includes a good decent selection, but have been picked up by gamers previously.
Neither of the games include the DLC, so those would need to be purchased and downloaded seperately.
The September 2019 line-up includes:
Batman: Arkham Knight (2015) has been around for a few years, so it the most likely to have been picked by gamers previously.