I couldn't find a list of included cards and neither a specific answer on this:

Are all cards included in the book? Or are the just supplements for easier play like how WotC does it for DnD.

I'm asking because almost no game stores seem to carry them in Europe and the markup ranges from 4-13€. I'm not willing to pay 20€ for 10 cards that are already included in the book simply to reference them easier.

If you're referring the the Adversary Decks then almost all of them are just quick reference cards of already existing NPC's in the base (respective) books.

The only one that adds some new NPC's added is Runners, Mercs, and Criminals .