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 Ruana just because of the illustrations: https://www.pamwishbow.com/client-work/project-four-yjynj-pafyx
Yeah it's Oath, I bought it, I don't even know if I'll be able to play it with friends, but I need all the Kyle Ferrin I can humanly collect in my life. His cute critters and goofy faces and lovely sketch lines and textures are just so adorable
Edit : btw I stole the pic from the first image search result I could find that showcased nice looking games, it's apparently from this article : https://gamerant.com/most-beautiful-board-game-boards/