Explore your Azure resources with Resource Graph
Azure Resource Graph is a service in Azure that is designed to extend Azure Resource Management by providing efficient and performant resource exploration with the ability to query at scale across all subscriptions and management groups so that you can effectively govern your environment.
Here you can start with simple queries in the Cloudshell
More information about Azure Resource Graph here
Just by playing with Azure Resource Graph you learn more what is behind the Azure Portal and your Subscription(s)