This link is for the website MusicPlay. This website contains all kinds of activities and exercises that could enrich your music learning. This site has more content for Primary students than Intermediate, however, there are activities that would challenge most Intermediate students. If you are looking for some fun online activities to explore rhythm, melody, instruments of the orchestra, you might enjoy exploring this site.
https://musiclab.chromeexperiments.com/
Chrome Music Lab is another great site. Use it to experiment with and explore sound, rhythm and melody.