ai2.appinventor.mit.edu
community.appinventor.mit.edu/tags
gallery.appinventor.mit.edu, register
puravidaapps.com/extensions.php
https://play.google.com/store/apps/details?id=edu.mit.appinventor.aicompanion3
https://apps.apple.com/us/app/mit-app-inventor/id1422709355