Yes... Bally's, Ceasars, Claridge, Harrah's, Sands and Showboat are all free with their basic slot club card. Borgata and Hilton offer free parking only to their premium card holders.

"I do have lots of all level cards (with other people's names). Would they work?"

Yes those other cards would work if they don't check ID's. I've been told Borgata occasionally checks. They want to squeeze every cent from you!