They're listed under the Terrible's casino management listing
When you look at the individual Terrible's casinos you should see a yellow band link indicating when they switched to the generic multi-property cards, or you might only find that yellow band link if there were no specific cards for any certain casino. The second box of the yellow band links has a link to the casino management listings or wherever the text indicates later card are located. If I missed a placement for one of the links let me know and I'll get it updated. There were 4 or 5 people all working on entering the slot card information and there might be a few things that were overlooked.
In any event, these are super common cards and typically only sell in with other cards since they only bring 10-20 cents a card. I have hundreds of them if you need more : - )