Modern Super Mario Bros. games utilize 3D-rendered character models in place of the sprite-based graphics of times gone by. That doesn't mean Nintendo wholly abandoned its 2D past, however: Almost every new Mario game is accompanied by charming hand-drawn character art. A dedicated Nintendo fan recently rounded up most of these unique artworks and placed them in a Google Drive for everyone to enjoy.
Redditor Cevan shared their Mario artwork archive via the Nintendo subreddit. (Here's a direct link to the Google Drive.) The archive even includes art from very recent releases like Luigi's Mansion 3 and Mario Kart Tour. It's amazing how much supplemental 2D art Nintendo creates for each new Mario title: Cevan managed to fill up nearly all of the 15 gigs allotted to them.
The majority of the illustrations are the work of Shigehisa Nakaue, an artist who's been with Nintendo since 2003. Nakaue's style resembles the earliest Mario illustrations made by Yoichi Kotabe, who left Nintendo in 2007 and is currently a freelance illustrator. Though Nakaue clearly takes inspiration from Kotabe's classic designs, he has a unique flair that adds a dash of rich color to Mario, Luigi, and the Mushroom Kingdom in general.
Brew some tea, get comfy, and click through the archive Cevan set up. Immerse yourself in Nakaue's lovely artwork, and ask yourself: Why hasn't Nintendo made a 2D Mario game using Nakaue's character models? I don't have anything against the current crop of 2D Mario games, but I won't deny the clean, smooth 3D models Nintendo utilizes for its 2D titles lack the personality of its old-school sprites. If Wario Land: Shake It! exists for the Wii, I see no reason why Nintendo couldn't give us something similar with Mario, Luigi, and the rest of the crew.
Maybe it'll happen someday. In the meantime, enjoy Nakaue's artwork.