Started by a hashtag in 2016, libraries, archives, and other cultural institutions around the world are sharing free coloring sheets and books based on materials in their collections. This website has links to many institutions taking part.
Most of the Monterey Bay Aquarium’s webcams are available during set hours, with reruns playing during downtime. (If you want to watch sea otters live, for example, you’ll need to tune in between 1PM and 1AM ET.)