I think for me it’s got to be wingspan

boardgamegeek.com/boardgame/266192/wingspan

It’s not the most complex game, but Dixit has really beautiful cards, in my opinion.

Parks has very pretty cards (they are by different artists so vary a fair bit)

I picked up Faraway recently and like the art on those cards - slightly surreal fantasy theme.

I came here to post Faraway as well!

Also Mysterium has similar good looking big cards! I suppose they are both in a sort of tarot format.

And Wyrmspan’s cards are very nice, if you prefer dragons!