Clockwise from top left: End of the Park by Lego Ant, Bill o' Lantern by Lego Ant, and Stravengerhaven Falls by Lego Ant
Vantablack by W
The above material is called vantablack, being the darkest manmade material, absorbing nearly 99.965% of all visible radiation (the spectrum of light that us humans can see). It's more expensive than gold- but you can't buy it. It's not a pigment. It's a material made of carbon nanotubes.
Window by W