The deck features 59 creatures cards - this includes all of the creatures from the main book and all of the supplements that have been published up to this point. There are also 17 'blank cards', to either make up your own monsters or for new monsters that may come in the future.
Each card features artwork by Barrett Stanley, some of which has never been seen before, plus all of the stats for that creature. So now you can pull out the cards for the creatures you know you are going to need during a game and keep them handy.
I'll admit, I haven't actually gotten my hands on a deck yet, but I'm sure excited about them!
Modiphius has them available now. North Star should have them soon. Shipments are still on their way to the USA and other destinations.