This is a site as well as two apps, one for videos and one for games. There are no ads and they are completely free. Just make sure to support your local PBS station, which helps fund them.
The videos and games are or/for characters/shows such as Daniel Tiger, Peg and Cat, Cyberchase, Curious George, and many, many more.
I wasn’t aware until I had kids, but most of these shows are produced in Canada and employ lots of comedians. Martin Short is the voice of Cat in the Hat, Gilbert Gottfried and Christopher Lloyd are voices in Cyberchase, etc.
There is a huge amount of content, all of it good.