I have the Google Now cards on my homescreen, which I enabled in Settings/Device/Multiple Widgets (set to On). Is that what you mean or are there different types of cards? You can also long press the Home key, then press on the "G" button between the Ram Manager and Task Manager buttons.
For some reason, the Multiple Widgets toggle is not available as an option under Settings/Device/ or Settings/Device/Lockscreen, although I seem to remember seeing it when I first had the phone. It may have something to do also with the fact that for screen lock, Swipe, Signature and None are grayed out; "Disabled by administrator, encryption policy, or credential storage." I unchecked all the device administrators (KIES, Android Device Manager, etc.) but they remain grayed out.
