Q-BLOCK is an online tool and gallery where you can create awesome works of art with 3d pixels (a.k.a. voxels), forget about that old 2d pixel art where you can only see mario in 2 dimensions, with this you can see the good ol' Mario in pixelated 3d. Check it out:
These are just examples, you can rotate them and see them from every angle in the website. You can also create your own, there are hundreds of works already in the gallery. Enjoy!
Link to the website.