I think I added a few hundred hotel room keys to my Delcampe store too, about half are casino and the other half regular hotels. There's over 2,300 different hotel key cards currently listed.
Here's a link to my hotel key card listings on Delcampe with the latest additions appearing first. You can use their search to look for anything specific you're looking for. I think the non-casino cards are listed first via this link.
If you just want to see casino hotel key cards, here's another think that will give just those, again with the latest listings appearing first. There's about 1,600+ casino room keys listed currently.