[DEPRECATED] As of Android Studio 4.1, the templates API was completely overhauled to use Intellij plugin extension point.
Android Studio 4.1 uses a new templating API which is visible but not public yet, although I haven't been able to get this to work. Unfortunately in the process, Google seem to have removed the old way of adding templates.
For those interested in tracking progress, you can star the issue on Google's issue tracker system here.
Room starter pack for Android Studio
Simple just coppy folder CrocodicRoom into your Android Studio content package
paste to /Applications/Android Studio.app/Contents/plugins/android/lib/templates/other/
paste to {ANDROID_STUDIO_LOCATION}/plugins/android/lib/templates/other/