For me Genshin Impact and Hades (including Hades II) are two examples. These games have relatively simple art styles in comparison to e.g. the realistically painted art of certain Blizzard games (WoW, Hearthstone hero portraits), but they are hard to learn even to someone more advanced in art creation.
Its just pixel art with an orthographic view. The 3d space makes it easier to code and not harder to create art for than any 2d game.