The Music Teachers National Association has provided links to websites for kids.
Common Sense Media’s Best Arts Education Apps and Websites (article) provides a list of resources for teaching music, some of which are free.
The National Gallery of Art (NGA) and MOMA provide resources for teachers, including lessons and interactives
PBS Learning Media provides resources and activies for
dance, music, theater, and visual arts: https://ca.pbslearningmedia.org/subjects/the-arts/
German, French, Japanese, Chinese, and Spanish: https://ca.pbslearningmedia.org/subjects/world-languages/