Wolfram Demonstrations offers over 12,000 demonstrations and simulations for everything from advanced science and physics to K-2 science to arts and architecture. There is something for every teacher on this site!
Auto Draw is an artificial intelligence experiment hosted by Google. Their AI Experiments is a showcase for simple experiments that make it easier for anyone to start exploring machine learning, through pictures, drawings, language, music, and more.
Google Arts & Culture Project
Google Arts & Culture features content from over 2000 leading museums and archives who have partnered with the Google Cultural Institute to bring the world’s greatest works of art into the hands of everyone.
Sketchpad is a sweet little utility for creative projects. When the Google Drive toggle is set, the contents save directly into the user’s Google Drive and nothing is stored on Sketchpad’s servers.
Teachers can create content using sketchpad.io as can students.
Silk is a really cool interactive, generative art site. It does not require a login, but has a camera icon in the top left corner for artists to take a photo of their creations.
Beyond art, this site would offer some fun learning about symmetry in math.