Anything from Leader Games and illustrated by Kyle Ferrin (Root, Oath, Fort...) feels like cheating but still, I absolutely adore their art style
Everdell, Photosynthesis, Parks, look nice as well
I also bought an updated edition of Costa Tuna just because of the illustrations: https://www.pamwishbow.com/client-work/project-four-yjynj-pafyx
When it comes to card art definitely Dixit. When I Dream also has really nice illustrations (and is pretty fun too).
I also played Mysterium ~~which was made by the same people behind Dixit~~ (I just checked and not at all, it's just the same mechanics with beautiful illustrations open to interpretation, my bad), and the game is a lot more engaging to me, but Dixit is one of the classics for french players!
Dixit sure had to be mentioned - when art is effectively your game mechanic it needs to be good. Though it depends on the card set, not a fan of the Dixit Odysey base set
dude, I LOVE When I Dream! Also the idea of putting the draw pile inside a bedframe and covering the unused top of the cards with a pillow is so genius and creative!
Ooh I had totally forgotten about the pillow thing. Yeah that bedframe is pretty cool