The cards cover several major religions: Christianity, Islam and Judaism, and some are just neutral, festive cards that will work for anyone.
We've counted a total of 18 designs, and most of them are animated.
But this is where things get slightly unusual. Once you post the card, it will appear in your own news feed; you cannot send it to someone else. You can, however, choose who can see it as you're sharing it.
Unfortunately, the option seems to show up once on top of your news feed and then disappear forever after you've dismissed it, which will likely have many users scratching their heads and browsing through Facebook's endless menus to find it again. The only way to access it — as far as we know — is to go to someone else's card and then choose the "Select card" option below.