Is sandbox the way to try out certain extensions now (instead of Cividemo)?
To try out extensions, I recommend setting up CiviCRM Buildkit. CiviCRM Buildkit makes the task of spinning up CiviCRM test instances (in multiple flavours) much easier, then you can try any extension you like on it - and have a more complete environment to test in.


https://github.com/civicrm/civicrm-buildkit