WikiArt - The Encyclopedia of Fine Art
DeviantArt - deviantART was created to entertain, inspire, and empower the artist in all of us.
ArtMajeur - +1 Million original artworks, Free Shipping Worldwide, Low prices guaranteed, 14 days return: buy all the art you love on Artmajeur!
Brush Ninja - Hand-drawn Animated Gif Creator
Artspace - Art platform to discover and buy contemporary art.
pixiv - pixiv is an illustration community service where you can post and enjoy creative work. A large variety of work is uploaded, and user-organized contests are frequently held as well.