If you want all cards just for artwork, just check Manyakis' Patreon or Twitter smh Why would you need card unlocks specifically.
Everything else is pretty much unlockable by playing just a little bit. Saddle up and start clearing Warden challenges if you don't have enough bits to unlock some of artworks, it really doesn't take all that much time. Otherwise it kinda kills the purpose of those things being unlockables. Or cheat, no one will care, although you still will have to put in some effort to do it.