Oh lord… I have such a collection and I feel like my favorite is always changing so you might get a different answer if you ask in a week but, for the moment… I’d probably say Light Seers.
I love everything about it. Rounded edges, slightly dark art style (without overdoing it and making everything negative) and the handwriting font for the names is totally my vibe.
It’s still the traditional RWS cards, so I know there are others like the Ethereal Visions deck that will actually change how you use the cards more than just the artwork but if you’re just asking about my current favorite then I just love the style of this one so much.