Not exactly online but: Computer Science Unplugged https://csunplugged.org/en/ https://csunplugged.org/en/ Bootstrap Materials https://www.bootstrapworld.org/

Not exactly online but: Computer Science Unplugged https://csunplugged.org/en/ https://csunplugged.org/en/ Bootstrap Materials https://www.bootstrapworld.org/ https://www.bootstrapworld.org/ Bootstrap you fill in by hand small programs using Racket, Shriram Krishnamurthi from Brown U has a good talk here about Bootstrap curriculum and pitfalls of trying to design a CS curriculum for kids if you're interested in creating your own https://youtu.be/5c0BvOlR5gs https://youtu.be/5c0BvOlR5gs