Musiclab, including Songmaker (explore sound and layers): https://musiclab.chromeexperiments.com/
GarageBand: Songwriting app with virtual instruments and sequencer. (Mac devices only)
iMovie: Make music videos. (Mac devices only)
Launchpad: Make and remix electronic music (Mac devices only)
Incredibox: Make loops using sounds generated by voice/beatboxing: https://www.incredibox.com/ (App also available but at a cost)
ChromeLab: https://musiclab.chromeexperiments.com/
Google’s Blob Opera: Manipulate individual blobs to create your own choral composition: https://artsandculture.google.com/experiment/blob-opera/AAHWrq360NcGbw?hl=en&cp=e30.